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Sample records for charpy v-notch impact

  1. Effects of V-notch dimensions on charpy impact test results for differently sized miniature specimens of ferritic steel

    International Nuclear Information System (INIS)

    In order to develop the small specimen technology in Charpy impact testing, the effects of V-notch dimensions on the test results were investigated for miniaturized specimens of a ferritic steel, Japanese Ferrite/Martensite Dual Phase Steel (JFMS). The miniaturized Charpy specimens had four different square cross-sections of 3.3, 2, 1.5 and 1 mm, and each of them had a variety of V-notch dimensions (notch depth, notch root radius and notch angle). All of the specimens were subjected to Charpy impact tests between 93 and 373 K using a specially instrumented impact machine. The fracture surfaces of all tested specimens were examined by scanning electron microscopy. The main results obtained are as follows: (1) The ductile-to-brittle transition temperature (DBTT) varied noticeably depending upon the notch dimensions, some of the DBTTs exceeding that of the full size specimens. (2) The DBTTs for the miniaturized specimens were uniquely defined by the elastic stress concentration factor, Kt, leading to an important aspect that the DBTT for the full size specimens can be directly obtained from the DBTT of the miniaturized specimens with a V-notch giving a suitable value of Kt. (3) The upper shelf energy (USE) was dependent only on notch depth or ligament size, indicating that the notch geometry was practically unimportant. When all of the measured USEs were normalized by Bb2 or (Bb)3/2 (B is the specimen thickness, b the ligament size), the normalized USEs of the miniaturized specimens agreed with that of the full size specimens within the range of ±15% except for one specimen whose notch root radius was as large as 0.25 mm. (4) The observed characteristics of fracture surface were essentially the same as those of the full size specimens. The measurement of lateral expansion, or ductility, was more useful in estimating the impact property of JFMS than that of fracture appearance (fibrous fracture). (author)

  2. Confocal microscopy-fracture reconstruction and finite element modeling characterization of local cleavage toughness in a ferritic/martensitic steel in subsized Charpy V-notch impact tests

    International Nuclear Information System (INIS)

    The confocal microscopy (CM)-fracture reconstruction (FR) method, coupled with scanning electron microscopy (SEM) fractography, was used to measure the critical notch deformation conditions at cleavage initiation for two subsized Charpy V-notch (CVN) specimen geometries of Japan ferritic/martensitic steel (JFMS). A new method was developed to permit FR of notched specimens. Three-dimensional finite element analysis (FEA) simulations of the notch and specimen deformation were used to estimate values of critical micro-cleavage fracture stress, σ*, and critical stressed area, A*. Since σ*-A* is independent of size and geometry, it provides a fundamental local measure of cleavage toughness

  3. Confocal microscopy-fracture reconstruction and finite element modeling characterization of local cleavage toughness in a ferritic/martensitic steel in subsized Charpy V-notch impact tests

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, T. E-mail: yamataku@fusion.imr.tohoku.ac.jp; Odette, G.R.; Lucas, G.E.; Matsui, H

    2000-12-01

    The confocal microscopy (CM)-fracture reconstruction (FR) method, coupled with scanning electron microscopy (SEM) fractography, was used to measure the critical notch deformation conditions at cleavage initiation for two subsized Charpy V-notch (CVN) specimen geometries of Japan ferritic/martensitic steel (JFMS). A new method was developed to permit FR of notched specimens. Three-dimensional finite element analysis (FEA) simulations of the notch and specimen deformation were used to estimate values of critical micro-cleavage fracture stress, {sigma}{sup *}, and critical stressed area, A{sup *}. Since {sigma}{sup *}-A{sup *} is independent of size and geometry, it provides a fundamental local measure of cleavage toughness.

  4. Effects of oxidation on the impact energy of Hastelloy S and Hastelloy C-4 Charpy V-notch specimens heated in air at 6000 to 8000C

    International Nuclear Information System (INIS)

    The 90SrF2 heat source being developed at PNL utilizes a Hastelloy S or Hastelloy C-4 outer capsule having a 0.5-in.-thick wall to contain the Hastelloy C-276 inner capsule. The primary objective of the study was to demonstrate that the air oxidation of the outer capsule that could occur during heat-source service would not degrade the ductility and Charpy impact strength of the capsule below the licensing requirements given in Section 1.1. The 90SrF2 heat source under development is intended for general-purpose use. Compatibility considerations limit the interface temperature between the 90SrF2 and Hastelloy C-276 inner capsule to a maximum of 8000C. The outer capsule surface temperature will be somewhat less than 8000C, and depending on the service, may be substantially lower. The oxidation tests were therefore carried out at 6000 to 8000C for exposures up to 10,000h to cover the range of temperature the outer capsule might expect to encounter in service. The results showed that the oxidation of Hastelloy S and Hastelloy C-4 in air at 6000 to 8000C is very slow, and both alloys form adherent oxide layers that serve to protect the underlying metal. Subsurface attack of Hastelloy S and Hastelloy C-4 due to oxidation was greater than expected, considering the slow oxidation rates of the two alloys at 6000 to 8000C. Estimates of subsurface attack, determined from micrographs of the oxidized specimens, showed erratic results and it was impossible to assign any type of rate equation to the subsurface attack. A conservative estimate of long-term effects can be made using a linear extrapolation of the test results. There were no significant differences between the room-temperature Charpy impact energy of Hastelloy S and Hastelloy C-4 specimens oxidized in air at 6000 to 8000C and control specimens heated in vacuum

  5. Charpy Impact Test on Polymeric Molded Parts

    OpenAIRE

    Alexandra Raicu

    2012-01-01

    The paper presents the Charpy impact tests on the AcrylonitrileButadiene-Styrene (ABS) polymeric material parts. The Charpy impact test, also known as the Charpy V-notch test, is a standardized strain rate test which determines the amount of energy absorbed by a material during fracture. This is a typical method described in ASTM Standard D 6110. We use for testing an Instron - Dynatup equipment which have a fully integrated hardware and software package that let us capture ...

  6. Results of charpy V-notch impact testing of structural steel specimens irradiated at ∼30 degrees C to 1 x 1016 neutrons/cm2 in a commercial reactor cavity

    International Nuclear Information System (INIS)

    A capsule containing Charpy V-notch (CVN) and mini-tensile specimens was irradiated at ∼ 30 degrees C (∼ 85 degrees F) in the cavity of a commercial nuclear power plant to a fluence of 1 x 1016 neutrons/cm2 (> 1MeV). The capsule included six CVN impact specimens of archival High Flux Isotope Reactor A212 grade B ferritic steel and five CVN impact specimens of a well-studied A36 structural steel. This irradiation was part of the ongoing study of neutron-induced damage effects at the low temperature and flux experienced by reactor supports. The plant operators shut down the plant before the planned exposure was reached. The exposure of these specimens produced no significant irradiation-induced embrittlement. Of interest were the data on unirradiated specimens in the L-T orientation machined from a single plate of A36 structural steel, which is the same specification for the structural steel used in some reactor supports. The average CVN energy of five unirradiated specimens obtained from one region of the plate and tested at room temperature was ∼ 99 J, while the energy of 11 unirradiated specimens from other locations of the same plate was 45 J, a difference of ∼ 220%. The CVN impact energies for all 18 specimens ranged from a low of 32 J to a high of 111 J. Moreover, it appears that the University of Kansas CVN impact energy data of the unirradiated specimens at the 100-J level are shifted toward higher temperatures by about 20 K. The results were an example of the extent of scatter possible in CVN impact testing. Generic values for the CVN impact energy of A36 should be used with caution in critical applications

  7. Results of charpy V-notch impact testing of structural steel specimens irradiated at {approximately}30{degrees}C to 1 x 10{sup 16} neutrons/cm{sup 2} in a commercial reactor cavity

    Energy Technology Data Exchange (ETDEWEB)

    Iskander, S.K.; Stoller, R.E.

    1997-04-01

    A capsule containing Charpy V-notch (CVN) and mini-tensile specimens was irradiated at {approximately} 30{degrees}C ({approximately} 85{degrees}F) in the cavity of a commercial nuclear power plant to a fluence of 1 x 10{sup 16} neutrons/cm{sup 2} (> 1MeV). The capsule included six CVN impact specimens of archival High Flux Isotope Reactor A212 grade B ferritic steel and five CVN impact specimens of a well-studied A36 structural steel. This irradiation was part of the ongoing study of neutron-induced damage effects at the low temperature and flux experienced by reactor supports. The plant operators shut down the plant before the planned exposure was reached. The exposure of these specimens produced no significant irradiation-induced embrittlement. Of interest were the data on unirradiated specimens in the L-T orientation machined from a single plate of A36 structural steel, which is the same specification for the structural steel used in some reactor supports. The average CVN energy of five unirradiated specimens obtained from one region of the plate and tested at room temperature was {approximately} 99 J, while the energy of 11 unirradiated specimens from other locations of the same plate was 45 J, a difference of {approximately} 220%. The CVN impact energies for all 18 specimens ranged from a low of 32 J to a high of 111 J. Moreover, it appears that the University of Kansas CVN impact energy data of the unirradiated specimens at the 100-J level are shifted toward higher temperatures by about 20 K. The results were an example of the extent of scatter possible in CVN impact testing. Generic values for the CVN impact energy of A36 should be used with caution in critical applications.

  8. Charpy Impact Test on Polymeric Molded Parts

    Directory of Open Access Journals (Sweden)

    Alexandra Raicu

    2012-09-01

    Full Text Available The paper presents the Charpy impact tests on the AcrylonitrileButadiene-Styrene (ABS polymeric material parts. The Charpy impact test, also known as the Charpy V-notch test, is a standardized strain rate test which determines the amount of energy absorbed by a material during fracture. This is a typical method described in ASTM Standard D 6110. We use for testing an Instron - Dynatup equipment which have a fully integrated hardware and software package that let us capture load information at very high speed from the impact tests.

  9. Experiment HFIR-MFE-T3 for low-temperature irradiation of miniaturized Charpy V-notch specimens of nickel-doped ferritic steels

    International Nuclear Information System (INIS)

    The HFIR-MFE-T3 experimental capsule is described. This experiment consists of miniature Charpy V-notch specimens of 12 Cr-1 MoVW and 12 Cr-1 MoVW-2 Ni alloys. The different levels of nickel will result in different helium levels generated during irradiation, and thus will allow for an evaluation of the effect of helium on impact properties. Irradiation of the capsule has started with projected fluence at midplane that will produce 10 dpa expected by January 1982

  10. Charpy V-notch properties and microstructures of narrow gap ferritic welds of a quenched and tempered steel plate

    Energy Technology Data Exchange (ETDEWEB)

    Powell, G.L.F.; Herfurth, G. [Commonwealth Scientific and Industrial Research Organization, Woodville (Australia)

    1998-11-01

    Multipass welds of quenched and tempered 50-mm-thick steel plate have been deposited by a single wire narrow gap process using both gas metal arc welding (GMAW) and submerged arc welding (SAW). Of the five welds, two reported much lower Charpy V-notch (CVN) values when tested at {minus} 20 C. The CVN toughness did not correlate with either the welding process or whether the power source was pulsed or nonpulsed. The only difference in the ferritic microstructure between the two welds of low Charpy values and the three of high values was the percentage of acicular ferrite. There was no effect of the percentage of as-deposited reheated zones intersected by the Charpy notch or the microhardness of the intercellular-dendritic regions. In all welds, austenite was the microconstituent between the ferrite laths. The percentage of acicular ferrite correlated with the presence of MnO, TiO{sub 2}, {gamma} Al{sub 2}O{sub 3}, or MnO. Al{sub 2}O{sub 3} as the predominant crystalline compound in the oxide inclusions. In turn, the crystalline compound depended on the aluminum-to-titanium ratio in both the weld deposits and the oxide inclusions. In addition to the presence of less acicular ferrite, the two welds that showed lower Charpy values also reported more oxide inclusions greater than 1 {micro}m in diameter. The combination of more oxide inclusions greater than 1 {micro}m and less acicular ferrite is considered to be the explanation for the lower Charpy values.

  11. Dynamic Toughness Testing of Pre-Cracked Charpy V-Notch Specimens. Convention ELECTRABEL - SCK-CEN

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E

    1999-04-01

    This document describes the experimental and analytical procedures which have been adopted at the laboratories of the Belgian Nuclear Research Centre SCK-CEN for performing dynamic toughness tests on pre-cracked Charpy-V specimens. Such procedures were chosen on the basis of the existing literature on the subject, with several updates in the data analysis stages which reflect more recent developments in fracture toughness testing. Qualification tests have been carried out on PCCv specimens of JRQ steel, in order to assess the reliability of the results obtained; straightforward comparisons with reference data have been performed, as well as more advanced analyses using the Master Curve approach. Aspects related to machine compliance and dynamic tup calibration have also been addressed.

  12. Assessment of Ductile-to-Brittle Transition Behavior of Localized Microstructural Regions in a Friction-Stir Welded X80 Pipeline Steel with Miniaturized Charpy V-Notch Testing

    Science.gov (United States)

    Avila, Julian A.; Lucon, Enrico; Sowards, Jeffrey; Mei, Paulo Roberto; Ramirez, Antonio J.

    2016-06-01

    Friction-stir welding (FSW) is an alternative welding process for pipelines. This technology offers sound welds, good repeatability, and excellent mechanical properties. However, it is of paramount importance to determine the toughness of the welds at low temperatures in order to establish the limits of this technology. Ductile-to-brittle transition curves were generated in the present study by using a small-scale instrumented Charpy machine and miniaturized V-notch specimens (Kleinstprobe, KLST); notches were located in base metal, heat-affected, stirred, and hard zones within a FSW joint of API-5L X80 Pipeline Steel. Specimens were tested at temperatures between 77 K (-196 °C) and 298 K (25 °C). Based on the results obtained, the transition temperatures for the base material and heat-affected zone were below 173 K (-100 °C); conversely, for the stirred and hard zones, it was located around 213 K (-60 °C). Fracture surfaces were characterized and showed a ductile fracture mechanism at high impact energies and a mixture of ductile and brittle mechanisms at low impact energies.

  13. Fracture Behavior and Delamination Toughening of Molybdenum in Charpy Impact Tests

    Science.gov (United States)

    Babinsky, K.; Primig, S.; Knabl, W.; Lorich, A.; Stickler, R.; Clemens, H.

    2016-09-01

    This study combines advanced characterization techniques with conventional Charpy impact tests to relate the mechanical properties to the microstructure of technically pure molybdenum, especially regarding its toughness. V-notched samples with different orientations were prepared from a rolled molybdenum plate in stress-relieved and recrystallized condition. The ductile-to-brittle transition-temperature was analyzed in terms of the delamination behavior influenced by the microstructure. A pronounced increase of toughness was found for specific oriented samples, which can be explained by macroscopic delamination. Elongated grains led to enhanced delamination in Charpy impact tests with variations for different orientations. In general, delamination occurs as a result of brittle fracture; however, an increase in toughness in the Charpy impact test can be provoked. This mechanism is called thin sheet toughening or delamination toughening. Electron backscatter diffraction measurements were performed to get a deeper knowledge about crack propagation and delamination behavior in the rolled plate. Recrystallization shifts the transition region to significantly higher temperatures, which is explained by the globular grain shape as well as grain boundary segregation. The occurrence of delamination is discussed, taking texture, grain shape and segregation effects into account.

  14. Evaluation of Charpy impact properties and fracture toughness for irradiated ferritic steels (3)

    International Nuclear Information System (INIS)

    Four kinds of ferritic steels, 61FK, 61FS, ASTM A213T9 (F9S) and NSCR9, were irradiated in SMIR-10 at 823 K to (3.2-9.0)x1026 n/m2 (E > 0.1 MeV) and subjected to instrumented Charpy impact tests. The absorbed energy, dynamic yield and maximum loads, brittle fracture load and the deflection to brittle fracture were measured as a function of test temperature and the ductile-to-brittle transition temperature (DBTT) and the upper shelf energy (USE) were evaluated. For the test, Charpy V-notch specimens, JIS-4, were used which had the dimensions of 10x2x55 mm and the V-notch geometry of notch root radius of 0.25 mm, notch of 2 mm and notch angle of 45 degrees. Main results obtained are as follows. 1) The DBTT was less dependent on neutron dose. The DBTT for the higher dose of (8.8-9.0)-1026 n/m2 increased in the order of 61FK, NSCR9, 61FS and F9S. 2) As the neutron dose increased, the USE decreased for 61FK, while it stayed almost constant for 61GS and increased for F9S. The USE for the higher dose decreased in the order of 61FK, NSCR9, 61FS and F9S, which was the same as the increasing order of DBTT. 3) The DBTT shifts, ΔDBTT, due to irradiation with the higher dose level increased in the order of 61FK, 61FS and NSCR9, except for F9S, where the DBTT in the unirradiated state is not available. 4) The change in USE, ΔUSE, due to irradiation with the higher dose increased in the order of 61FS, 61FK and NSCR9, except for F9S. 5) Comparison of the present results with the previous ones irradiated at 723K in SMIR-10 showed that 823K irradiation caused considerably larger embrittlement than 723K irradiation, especially for F9S and 61FK. (author)

  15. Evaluation of Charpy impact properties and fracture toughness for irradiated ferritic steels. 2

    International Nuclear Information System (INIS)

    The instrumented Charpy impact test was performed for two PMC-FM steels, 61FK and 61FS, irradiated at 723 K to 9.0 x 1026 n/m2 (E > 0.1 MeV) in SMIR-10, and the other two steels, ASTM A213T9 and NSCR9, irradiated at 723 K to 3.6 x 1026 n/m2 in SMIR-10. The test was also conducted for unirradiated 61FK. The absorbed energy, dynamic yield load, dynamic maximum load and brittle fracture load were measured as a function of test temperature and the ductile-to-brittle transition temperature (DBTT) and the upper shelf energy (USE) were evaluated. The DBTT was determined in three different ways; the temperature at which the total absorbed energy was one half of USE (DBTT1), the temperature at which the dynamic yield and maximum loads were equal (DBTT2), and the temperature at which the total absorbed energy was equal to 2 J which corresponds to 10 J for full size specimens (DBTT3). For the test, Charpy V-notch specimens, JIS-4, were used which had the dimensions of 10 x 2 x 55 mm and the V-notch geometry of notch root radius of 0.25 mm, notch depth of 2 mm and notch angle of 45 degrees. Main results obtained are as follows. 1) The DBTT showed that DBTT1>DBTT2>DBTT3 for 61FK, 61FS and NSCR9. 2) For unirradiated 61FK the DBTT1 was 202 K and the USE was 16.9 J, while for irradiated 61FK the DBTT1 was 249 K and the USE was 10.8 J. Therefore, the irradiation caused the DBTT1 to increase by 47 K and the USE to decrease by 6.1 J. 3) For irradiated 61FS the DBTT1 was 207 K and the USE was 17.0 J. Since the DBTT1 and USE of unirradiated 61FS were 160 K and 20 J, respectively, it followed that the irradiation caused the DBTT1 to increase by 47 K and the USE to decrease by 3 J. 4) For irradiated F9S the DBTT1 was 166 K and the USE was 21.4 J. 5) For irradiated NSCR9 the DBTT1 was 208 K and the USE was 16.2 J. Since the DBTT1 and USE of unirradiated NSCR9 were 185 K and 16 J, respectively, it followed that the irradiation caused the DBTT1 to increase by 23 K but no decrease in USE. (J.P.N.)

  16. Quality assurance of absorbed energy in Charpy impact test

    Science.gov (United States)

    Rocha, C. L. F.; Fabricio, D. A. K.; Costa, V. M.; Reguly, A.

    2016-07-01

    In order to ensure the quality assurance and comply with standard requirements, an intralaboratory study has been performed for impact Charpy tests, involving two operators. The results based on ANOVA (Analysis of Variance) and Normalized Error statistical techniques pointed out that the execution of the tests is appropriate, because the implementation of quality assurance methods showed acceptable results.

  17. Microstructural characterization of Charpy-impact-tested nanostructured bainite

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Y.T.; Chang, H.T.; Huang, B.M. [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC (China); Huang, C.Y. [Iron and Steel R& D Department, China Steel Corporation, Kaohsiung, Taiwan, ROC (China); Yang, J.R., E-mail: jryang@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC (China)

    2015-09-15

    In this work, a possible cause of the extraordinary low impact toughness of nanostructured bainite has been investigated. The microstructure of nanostructured bainite consisted chiefly of carbide-free bainitic ferrite with retained austenite films. X-ray diffractometry (XRD) measurement indicated that no retained austenite existed in the fractured surface of the Charpy-impact-tested specimens. Fractographs showed that cracks propagated mainly along bainitic ferrite platelet boundaries. The change in microstructure after impact loading was verified by transmission electron microscopy (TEM) observations, confirming that retained austenite was completely transformed to strain-induced martensite during the Charpy impact test. However, the zone affected by strained-induced martensite was found to be extremely shallow, only to a depth of several micrometers from the fracture surface. It is appropriately concluded that upon impact, as the crack forms and propagates, strain-induced martensitic transformation immediately occurs ahead of the advancing crack tip. The successive martensitic transformation profoundly facilitates the crack propagation, resulting in the extremely low impact toughness of nanostructured bainite. Retained austenite, in contrast to its well-known beneficial role, has a deteriorating effect on toughness during the course of Charpy impact. - Highlights: • The microstructure of nanostructured bainite consisted of nano-sized bainitic ferrite subunits with retained austenite films. • Special sample preparations for SEM, XRD and TEM were made, and the strain-affected structures have been explored. • Retained austenite films were found to transform into martensite after impact loading, as evidenced by XRD and TEM results. • The zone of strain-induced martensite was found to extend to only several micrometers from the fracture surface. • The poor Charpy impact toughness is associated with the fracture of martensite at a high strain rate during

  18. Microstructural characterization of Charpy-impact-tested nanostructured bainite

    International Nuclear Information System (INIS)

    In this work, a possible cause of the extraordinary low impact toughness of nanostructured bainite has been investigated. The microstructure of nanostructured bainite consisted chiefly of carbide-free bainitic ferrite with retained austenite films. X-ray diffractometry (XRD) measurement indicated that no retained austenite existed in the fractured surface of the Charpy-impact-tested specimens. Fractographs showed that cracks propagated mainly along bainitic ferrite platelet boundaries. The change in microstructure after impact loading was verified by transmission electron microscopy (TEM) observations, confirming that retained austenite was completely transformed to strain-induced martensite during the Charpy impact test. However, the zone affected by strained-induced martensite was found to be extremely shallow, only to a depth of several micrometers from the fracture surface. It is appropriately concluded that upon impact, as the crack forms and propagates, strain-induced martensitic transformation immediately occurs ahead of the advancing crack tip. The successive martensitic transformation profoundly facilitates the crack propagation, resulting in the extremely low impact toughness of nanostructured bainite. Retained austenite, in contrast to its well-known beneficial role, has a deteriorating effect on toughness during the course of Charpy impact. - Highlights: • The microstructure of nanostructured bainite consisted of nano-sized bainitic ferrite subunits with retained austenite films. • Special sample preparations for SEM, XRD and TEM were made, and the strain-affected structures have been explored. • Retained austenite films were found to transform into martensite after impact loading, as evidenced by XRD and TEM results. • The zone of strain-induced martensite was found to extend to only several micrometers from the fracture surface. • The poor Charpy impact toughness is associated with the fracture of martensite at a high strain rate during

  19. Enhancement of Charpy impact value by electron beam irradiation of carbon fiber reinforced polymer

    International Nuclear Information System (INIS)

    Influences of electron beam irradiation on Charpy impact value of carbon fiber reinforced polymer (CFRP) have been investigated. The irradiation, which is one of short-time treatments, enhanced the Charpy impact value of CFRP. Furthermore, strengthening of carbon fiber, ductility enhancement of polymer and interface effects on impact test explains the impact value enhancement of CFRP. (author)

  20. Effects of nonstandard heat treatment temperatures on tensile and Charpy impact properties of carbon-steel casting repair welds

    International Nuclear Information System (INIS)

    This report discusses carbon steel castings which are used for a number of different components in nuclear power plants, including valve bodies and bonnets. Components are often repaired by welding processes, and both welded components and the repair welds are subjected to a variety of postweld heat treatments (PWHT) with temperatures as high as 899 degrees C (1650 degrees F), well above the normal 593 to 677 degrees C (1100 to 1250 degrees F) temperature range. The temperatures noted are above the A1 transformation temperature for the materials used for these components. A test program was conducted to investigate the potential effects of such ''nonstandard'' PWHTs on mechanical properties of carbon steel casting welds. Four weldments were fabricated, two each with the shielded-metal-arc (SMA) and flux-cored-arc (FCA) processes,with a high-carbon and low-carbon filler metal in each case. All four welds were sectioned and given simulated PWHTs at temperatures from 621 to 899 degrees C (1150 to 1650 degrees F) in increments of 56 degrees C (100 degrees F) and for times of 5, 10, 20, and 40 h at each temperature. Hardness, tensile, and Charpy V-notch (CVN) impact tests were conducted for the as-welded and heat-treated conditions

  1. Numerical modelling of Charpy-V notch test by local approach to fracture. Application to an A508 steel in the ductile-brittle transition range; Modelisation de l'essai Charpy par l'approche locale de la rupture. Application au cas de l'acier 16MND5 dans le domaine de transition

    Energy Technology Data Exchange (ETDEWEB)

    Tanguy, B

    2001-07-15

    Ferritic steels present a transition of the rupture mode which goes progressively of a brittle rupture (cleavage) to a ductile rupture when the temperature increases. The following of the difference of the transition temperature of the PWR vessel steel by the establishment of toughness curves makes of the Charpy test an integrating part of the monitoring of the French PWR reactors. In spite of the advantages which are adapted to it in particular its cost, the Charpy test does not allow to obtain directly a variable which characterizes a crack propagation resistance as for instance the toughness used for qualifying the mechanical integrity of a structure. This work deals with the establishment of the through impact strength-toughness in the transition range of the vessel steel: 16MND5 from a non-empirical approach based on the local approach of the rupture. The brittle rupture is described by the Beremin model (1983), which allows to describe the dispersion inherent in this rupture mode. The description of the brittle fissure is carried out by the GTN model (1984) and by the Rousselier model (1986). This last model has been modified in order to obtain a realistic description of the brittle damage in the case of fast solicitations and of local heating. The method proposed to determine the parameters of the damage models depends only of tests on notched specimens and of the inclusion data of the material. The behaviour is described by an original formulation parametrized in temperature which allows to describe all the tests carried out in this study. Before using this methodology, an experimental study of the behaviour and of the rupture modes of the steel 16MND5 has been carried out. From the toughness tests carried out in quasi-static and dynamical conditions, it has been revealed that this steel does not present important unwedging of its toughness curve due to the velocity effect. In the transition range, local heating of about 150 C have been measured in the root

  2. Reconstitution technology of Charpy surveillance specimens with short insert length

    International Nuclear Information System (INIS)

    As for the shortage of the surveillance specimens to monitor the effect of the irradiation embrittlement of reactor pressure vessels (RPV) materials in case of longer-term operation than present surveillance program of nuclear power plants, the reconstitution of them is considered to be the promising measures. Although the length of the specimen insert is required not less than 18 mm in ASTM E1253-99 which is the technical standard to reconstitute Charpy specimens, the minimum length of the specimen insert required should be 10 mm when L-T direction Charpy specimens that have been applied to the early domestic nuclear power plants are reconstituted into T-L direction specimens in order to test the upper shelf absorbed energy of T-L direction specimens. This paper presents the current status of the research consigned by Ministry of Economy, Trade and Industry (METI) in Japan on the applicability of the reconstituted Charpy specimens with short length of the specimen insert. The length of the specimen insert to preserve the absorbed energy of the Charpy specimen is correlated to the absorbed energy of its material. The significant part of upper shelf energy is attributed to the energy for the plastic deformation zone near V-notch in the Charpy specimen. To preserve the absorbed energy, the anticipated plastically deformed zone shall not be affected by the reconstitution procedure. In order to clarify the condition for preserving the absorbed energy in the case of reconstitution, the preliminary data has been obtained using un-irradiated and irradiated Charpy specimens, and the following results have been obtained by the tests carried out in this research. 1) The plastic deformation widths have been estimated by measuring the hardness distribution near the V-notch of the un-irradiated Charpy impact tested specimens, correlated to the absorbed energy. 2) The absorbed energy shifts of reconstituted, un-irradiated Charpy specimens with various length of the specimen

  3. An improved correlation procedure for subsize and full-size Charpy impact specimen data

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, M.A.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1997-03-01

    The possibility of using subsize specimens to monitor the properties of reactor pressure vessel steels is receiving increasing attention for light-water reactor plant life extension. This potential results from the possibility of cutting samples of small volume form the internal surface of the pressure vessel for determination of the actual properties of the operating pressure vessel. In addition, plant life extension will require supplemental data that cannot be provided by existing surveillance programs. Testing of subsize specimens manufactured from broken halves of previously tested surveillance Charpy specimens offers an attractive means of extending existing surveillance programs. Using subsize Charpy V-notch-type specimens requires the establishment of a specimen geometry that is adequate to obtain a ductile-to-brittle transition curve similar to that obtained from full-size specimens, and the development of correlations for transition temperature and upper-shelf energy (USE) level between subsize and full-size specimens. Five different geometries of subsize specimens were selected for testing and evaluation. The specimens were made from several types of pressure vessel steels with a wide range of yield strengths, transition temperatures, and USEs. The effects of specimen dimensions, including notch depth, angle, and radius, have been studied. The correlations of transition temperatures determined from different types of subsize specimens and the full-size specimens are presented. A new procedure for transforming data from subsize specimens is developed. The transformed data are in good agreement with data from full-size specimens for materials that have USE levels less than 200 J.

  4. Magnetic system for the quality control of specimens for Charpy impact test

    Science.gov (United States)

    Martin, R. V.; Castanho, M. A. P.

    2015-10-01

    It was developed a non-destructive testing system based on magnetic methods for characterization of steel specimens, used in calibration of Charpy impact testing machines. The magnetic properties saturation, remanence, coercivity, and the hysteresis curves were used to create a "magnetic signature" of reference to ensure the value of energy absorbed by these standard specimens.

  5. Tensile and charpy impact properties of irradiated reduced-activation ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    Tensile tests were conducted on eight reduced-activation Cr-W steels after irradiation to 15-17 and 26-29 dpa, and Charpy impact tests were conducted on the steels irradiated to 26-29 dpa. Irradiation was in the Fast Flux Test Facility at 365{degrees}C on steels containing 2.25-12% Cr, varying amounts of W, V, and Ta, and 0.1%C. Previously, tensile specimens were irradiated to 6-8 dpa and Charpy specimens to 6-8, 15-17, and 20-24 dpa. Tensile and Charpy specimens were also thermally aged to 20000 h at 365{degrees}C. Thermal aging had little effect on the tensile behavior or the ductile-brittle transition temperature (DBTT), but several steels showed a slight increase in the upper-shelf energy (USE). After {approx}7 dpa, the strength of the steels increased and then remained relatively unchanged through 26-29 dpa (i.e., the strength saturated with fluence). Post-irradiation Charpy impact tests after 26-29 dpa showed that the loss of impact toughness, as measured by an increase in DBTT and a decrease in the USE, remained relatively unchanged from the values after 20-24 dpa, which had been relatively unchanged from the earlier irradiations. As before, the two 9Cr steels were the most irradiation resistant.

  6. Evaluation of Charpy impact properties and fracture toughness for irradiated ferritic steels (4)

    International Nuclear Information System (INIS)

    In order to evaluate the radiation-induced shift of fracture toughness from Charpy impact test results for miniaturized specimens, all of the Charpy impact data on high-strength ferritic steels developed by JNC were examined on the basis of the recent progress on the Charpy impact and fracture toughness test methods. Main results obtained are as follows. 1. The radiation-induced shift of fracture toughness is characterized by the shift of the reference fracture toughness temperature, ΔT100, where T100 is the temperature at which the fracture toughness value is 100MPa√ m. ΔT100 is approximately equal to the radiation-induced shift of Charpy DBTT at 41J (ΔT41). Therefore, ΔT100 can be estimated by determining ΔT41 from miniaturized Charpy specimen data. 2. The value of T41 for miniaturized specimens, T41M, can be determined as the test temperature where the absorbed energy is equal to 41/αx[(Bb)3/2F/(Bb)3/2M]. Here, B is the specimen thickness, b is the ligament size and αx[(Bb)3/2F/(Bb)3/2M] is the normalization factor to get the upper shelf energy of full size specimens, USEF, from the mini-size USEM. The values of α is larger than 0.65, depending on the USE of the material. It is also shown that the fracture volume of (Bb)3/2 is more valid than that of Bb2. 3. The following relationship appears to hold between T41F and T41M. T41F - T41M=M=98 - 15.1xln(Bb)3/2, where M is the specimen size correction factor. M also depends on notch geometry and its dependence becomes large with decreasing specimen size. This indicates that the value of T41F can be estimated from T41M by choosing suitable notch geometry. 4. The radiation-induced shift of T41F, ΔT41F, is approximately equal to ΔT41M. This indicates that the estimate of ΔT100 can be made from ΔT41M. 5. For all of the miniaturized Charpy specimen data on high-strength ferritic steels that were irradiated in JOYO and tested at Tohoku University, the values of USEF, T41F, ΔT41F and ΔT100 were successfully

  7. Relation between Charpy impact properties and magnetism in thermally aged Fe-Cu model alloys

    International Nuclear Information System (INIS)

    This study demonstrates the possibility of applying magnetic methods to pressure vessel surveillance for irradiation embrittlement at nuclear power plants. Charpy impact test and magnetic hesteresis measurement were preformed on thermally aged Fe-1.0wt%Cu model alloys with and without pre-deformation. DBTT increased with increasing aging time. However, magnetic hysteresis parameters showed nonmonotonical changes. The phenomena are discussed in terms of Cu precipitation behavior and dislocation structure. (author)

  8. Behavior of Aramid Fiber/Ultrahigh Molecular Weight Polyethylene Fiber Hybrid Composites under Charpy Impact and Ballistic Impact

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The aramid fiber/UHMWPE (ultrahigh molecular weight polyethylene) fiber hybrid composites (AF/DF) were manufactured. By Charpy impact, the low velocity impact behavior of AF/DF composite was studied. And the high velocity impact behavior under ballistic impact was also investigated. The influence of hybrid ratio on the performances of low and high velocity impact was analyzed, and hybrid structures with good impact properties under low velocity impact and high velocity were optimized. For Charpy impact, the maximal impact load increased with the accretion of the AF layers for AF/DF hybrid composites. The total impact power was reduced with the decrease of DF layers and the delamination can result in the increase of total impact power. For ballistic impact, the DF ballistic performance was better than that of the AF and the hybrid ratio had a crucial influence. The failure morphology of AF/DF hybrid composite under Charpy impact and ballistic impact was analyzed. The AF/DF hybrid composites in suitable hybrid ratio could attain better performance than AF or DF composites.

  9. A New Analytical Expression for the Relationship Between the Charpy Impact Energy and Notch Tip Position for Functionally Graded Steels

    Institute of Scientific and Technical Information of China (English)

    H.Samareh Salavati Pour; F.Berto; Y.Alizadeh

    2013-01-01

    The effect of the distance between the notch tip and the position of the middle phase in the FGSs on the Charpy impact energy is investigated in the present paper.The results show that when the notch apex is close to the middle layer,the Charpy impact energy reaches its maximum value.This is due to the increment of the absorbed energy by plastic deformation ahead of the notch tip.On the other hand,when the notch tip is far from the middle layer,the Charpy impact energy strongly decreases.Another fundamental motivation of the present work is that for crack arrester configuration,no accurate mathematical or analytical modelling is available up to now.By considering the relationship between the Charpy impact energy and the plastic volume size,a new theoretical model has been developed to link the Charpy impact energy with the distance from the notch apex to the middle phase.This model is a simplified one and the effect of different shapes of the layers and the effect of microstructure on the mechanical properties and plastic region size will be considered in further investigation.The results of the new developed closed form expression show a sound agreement with some recent experimental results taken from the literature.

  10. Validation Study of Unnotched Charpy and Taylor-Anvil Impact Experiments using Kayenta

    Energy Technology Data Exchange (ETDEWEB)

    Kamojjala, Krishna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lacy, Jeffrey [Idaho National Lab. (INL), Idaho Falls, ID (United States); Chu, Henry S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Brannon, Rebecca [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    Validation of a single computational model with multiple available strain-to-failure fracture theories is presented through experimental tests and numerical simulations of the standardized unnotched Charpy and Taylor-anvil impact tests, both run using the same material model (Kayenta). Unnotched Charpy tests are performed on rolled homogeneous armor steel. The fracture patterns using Kayenta’s various failure options that include aleatory uncertainty and scale effects are compared against the experiments. Other quantities of interest include the average value of the absorbed energy and bend angle of the specimen. Taylor-anvil impact tests are performed on Ti6Al4V titanium alloy. The impact speeds of the specimen are 321 m/s and 393 m/s. The goal of the numerical work is to reproduce the damage patterns observed in the laboratory. For the numerical study, the Johnson-Cook failure model is used as the ductile fracture criterion, and aleatory uncertainty is applied to rate-dependence parameters to explore its effect on the fracture patterns.

  11. Experimental study on variations in Charpy impact energies of low carbon steel, depending on welding and specimen cutting method

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhaorui; Kang, Hansaem; Lee, Young Seog [Chung-Ang University, Seoul (Korea, Republic of)

    2016-05-15

    This paper presents an experimental study that examines variations of Charpy impact energy of a welded steel plate, depending upon the welding method and the method for obtaining the Charpy specimens. Flux cored arc welding (FCAW) and Gas tungsten arc welding (GTAW) were employed to weld an SA516 Gr. 70 steel plate. The methods of wire cutting and water-jet cutting were adopted to take samples from the welded plate. The samples were machined according to the recommendations of ASTM SEC. II SA370, in order to fit the specimen dimension that the Charpy impact test requires. An X-ray diffraction (XRD) method was used to measure the as-weld residual stress and its redistribution after the samples were cut. The Charpy impact energy of specimens was considerably dependent on the cutting methods and locations in the welded plate where the specimens were taken. The specimens that were cut by water jet followed by FCAW have the greatest resistance-to-fracture (Charpy impact energy). Regardless of which welding method was used, redistributed transverse residual stress becomes compressive when the specimens are prepared using water-jet cutting. Meanwhile, redistributed transverse residual stress becomes tensile when the specimens are prepared using wire cutting.

  12. Correlation of microstructure and charpy impact properties in API X70 and X80 line-pipe steels

    International Nuclear Information System (INIS)

    This study aims at correlating microstructure and Charpy impact properties in high-toughness API X70 and X80 line-pipe steels. Three kinds of steels were fabricated by varying alloying elements and hot rolling conditions, and their microstructures and Charpy impact properties were investigated. In addition, their effective grain sizes were characterized by the electron back-scatter diffraction (EBSD) analysis. The Charpy impact test results indicated that the steels rolled in the single phase region had the higher upper shelf energy (USE) than the steel rolled in the two phase region because their microstructures were composed of acicular ferrites. In the X80 steel rolled in the single phase region, the decreased energy transition temperature (ETT) could be explained by the decrease in the overall effective grain size due to the presence of acicular ferrite having smaller effective grain size. Thus, it had excellent mechanical properties in yield and tensile strengths, absorbed energy, and transition temperature, except in ductility

  13. Constraint effects on fracture toughness of impact-loaded, precracked Charpy specimens

    International Nuclear Information System (INIS)

    Impact-loaded, precracked Charpy specimens often play a crucial role in irradiation surveillance programs for nuclear power plants. However, the small specimen size B=W=10 mm limits the maximum value of cleavage fracture toughness Jc that can be measured under elastic-plastic conditions without loss of crack tip constraint. In this investigation, plane strain impact analyses provide detailed resolution of crack tip fields for impact-loaded specimens. Crack tip stress fields are characterized in terms of J-Q trajectories and the toughness-scaling model which is applicable for a cleavage fracture mechanism. Results of the analyses suggest deformation limits at fracture in the form of b>MJc/σ0, where M approaches 25-30 for a strongly rate-sensitive material at impact velocities of 3-6 m s-1. Based on direct comparison of the static and dynamic J values computed using a domain integral formulation, a new proposal emerges for the transition time, the time after impact at which interial effects diminish sufficiently for simple evaluation of J using the plastic η factor approach. (orig.)

  14. Response of unirradiated and neutron-irradiated vanadium alloys to Charpy-impact loading

    International Nuclear Information System (INIS)

    The ductile-brittle transition temperature (DBTT) was determined by Charpy-impact impact tests for dehydrogenated (<30 appm H) and hydrogenated (400--1200 appm H) V-7.2Cr-14.5Ti, V-9.9Cr-9.2Ti, V-13.5Cr-5.2Ti, V-17.7Ti, V-9.2Cr-4.9Ti, V-9.0Cr-3.2Fe-1.2Zr, V-3.1Ti-0.5Si, V-4.1Cr-4.3Ti, V-4.6Ti, and V-2.5Ti-1.0Si alloys. The DBTT was also determined for the V-13.5Cr-5.2Ti, V-9.2Cr-4.9Ti, V-7.2Cr-14.5Ti, and V-17.7Ti alloys after neutron irradiation at 420 and 600 degrees C to 41--44 atom displacements per atom. The DBTTs determined for these vanadium alloys show that a vanadium alloy containing Cr and/or Ti and Si alloying additions to be used as a structural material in a fusion reactor should contain 3--11 wt % total alloying addition for maximum resistance to hydrogen- and/or irradiation-induced embrittlement. 4 refs., 3 figs., 2 tabs

  15. A reassessment of the effects of helium on Charpy impact properties of ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Gelles, D.S.; Hamilton, M.L. [Pacific Northwest National Lab., Richland, WA (United States); Hankin, G.L. [Loughborough Univ. (United Kingdom)

    1998-03-01

    To test the effect of helium on Charpy impact properties of ferritic/martensitic steels, two approaches are reviewed: quantification of results of tests performed on specimens irradiated in reactors with very different neutron spectra, and isotopic tailoring experiments. Data analysis can show that if the differences in reactor response are indeed due to helium effects, then irradiation in a fusion machine at 400 C to 100 dpa and 1000 appm He will result in a ductile to brittle transition temperature shift of over 500 C. However, the response as a function of dose and helium level is unlikely to be simply due to helium based on physical reasoning. Shear punch tests and microstructural examinations also support this conclusion based on irradiated samples of a series of alloys made by adding various isotopes of nickel in order to vary the production of helium during irradiation in HFIR. The addition of nickel at any isotopic balance to the Fe-12Cr base alloy significantly increased the shear yield and maximum strengths of the alloys. However, helium itself, up to 75 appm at over 7 dpa appears to have little effect on the mechanical properties of the alloys. This behavior is instead understood to result from complex precipitation response. The database for effects of helium on embrittlement based on nickel additions is therefore probably misleading and experiments should be redesigned to avoid nickel precipitation.

  16. Fractographic examination of Charpy impact specimens from the HFIR-MFE-RB2 test

    International Nuclear Information System (INIS)

    The objective of this work is to determine the effect of low temperature irradiation in HFIR on the properties of ferritic stainless steels in order to determine the applicability of these alloys as first wall materials. Selected fracture surfaces of miniature Charpy specimens of HT-9 in base metal, weld metal and heat affected zone (HAZ) metal conditions, and 9Cr-1Mo in base metal and weld metal conditions have been examined by scanning electron microscopy following irradiation in High Flux Isotope Reactor-Magnetic Fusion Energy-RB2 at 550C to 10 dpa. Hardness measurements have also been made. Comparison of results with results on specimens irradiated to low dose demonstrates only minor changes in fracture behavior, but continued increases in hardness due to irradiation. Therefore, the mechanism controlling the degradation of impact properties does not affect the fracture path but does affect strength. A mechanism is proposed to explain the behavior based on microchemical segregation of carbide forming elements. 5 references, 10 figures, 1 table

  17. Application of Charpy Impact Absorbed Energy to the Safety Assessment Based on SINTAP

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The European Structural Integrity Assessment Procedure(SINTAP) was applied to the assessment of welded joints of the APl 5L X65 pipeline steel with an assumed embedded flaw and surface flaw at the weld toe. At default level( level 0), the assessment point was established by estimating fracture toughness value KIc conservatively from Charpy energy test data. At the same time, the analysis level 1 (basic level)was applied based on the fracture toughness CTOD. Then the two assessment levels were compared. The assessment results show that all assessment points are located within the failure lines of analysis levels 0 and 1. So the welded joint of the pipeline is safe. It can be concluded that the assessment based on Charpy absorbed energy is practicable when other fracture toughness data are not available, or cannot be easily obtained. The results are conservative.

  18. Weld investigations by 3D analyses of Charpy V-notch specimens

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, Allan

    2005-01-01

    -viscoplastic constitutive relation for a porous plastic solid, accounting for adiabatic heating due to plastic dissipationfiand the resulting thermal softening. The onset of cleavage is taken to occur when the average of the maximum principal stress over a speci¯ed volume attains a critical value. Typically, the material...

  19. Effects of thermal aging on fracture toughness and Charpy-impact strength of stainless steel pipe welds

    International Nuclear Information System (INIS)

    Degradation of fracture toughness, tensile, and Charpy-impact properties of Type 304 and 304/308 SS pipe welds due to thermal aging was studied at room temperature and 290 C. Thermal aging of SS welds results in moderate decreases in charpy-impact strength and fracture toughness. Upper-shelf energy decreased by 50-80 J/cm2. Decrease in fracture toughness J-R curve or JIC is relatively small. Thermal aging had no or little effect on tensile strength of the welds. Fracture properties of SS welds are controlled by the distribution and morphology of second-phase particles. Failure occurs by formation and growth of microvoids near hard inclusions; such processes are relatively insensitive to thermal aging. The ferrite phase has little or no effect on fracture properties of the welds. Differences in fracture resistance of the welds arise from differences in the density and size of inclusions. Mechanical-property data from the present study are consistent with results from other investigations. The existing data have been used to establish minimum expected fracture properties for SS welds

  20. Tensile and Charpy impact behavior of an irradiated three-wire series-arc stainless steel cladding

    International Nuclear Information System (INIS)

    The potential for stainless steel cladding to improve the fracture behavior of an operating nuclear reactor pressure vessel, particularly during certain overcooling transients, may depend greatly on the properties of the irradiated cladding. Therefore, three-wire stainless steel cladding irradiated at temperatures and to fluences relevant to power reactor operation was examined. Postirradiation testing results show that, in the test temperature range from -125 to 288 degrees C, the yield strength increased by 8 to 30%, and ductility insignificantly increased, while there was almost no change in the ultimate tensile strength. All cladding exhibited ductile-to-brittle transition behavior during Charpy impact testing, owing to the dominance of delta-ferrite failures at low temperatures. On the upper shelf, the energy was reduced (owing to irradiation exposure) 15 to 20%, while the lateral expansion was reduced 43 and 41% at 2 and 5 - 1019 n/cm2 (E > 1 MeV), respectively. In addition, radiation damage resulted in 13 and 28 degrees C shifts of the Charpy impact transition temperature at the 41-J level for the low and high fluences, respectively

  1. Effects of thermal aging on fracture toughness and Charpy-impact strength of stainless steel pipe welds

    Energy Technology Data Exchange (ETDEWEB)

    Gavenda, D.J.; Michaud, W.F.; Galvin, T.M.; Burke, W.F.; Chopra, O.K. [Argonne National Lab., IL (United States)

    1996-05-01

    Degradation of fracture toughness, tensile, and Charpy-impact properties of Type 304 and 304/308 SS pipe welds due to thermal aging was studied at room temperature and 290 C. Thermal aging of SS welds results in moderate decreases in charpy-impact strength and fracture toughness. Upper-shelf energy decreased by 50-80 J/cm{sup 2}. Decrease in fracture toughness J-R curve or J{sub IC} is relatively small. Thermal aging had no or little effect on tensile strength of the welds. Fracture properties of SS welds are controlled by the distribution and morphology of second-phase particles. Failure occurs by formation and growth of microvoids near hard inclusions; such processes are relatively insensitive to thermal aging. The ferrite phase has little or no effect on fracture properties of the welds. Differences in fracture resistance of the welds arise from differences in the density and size of inclusions. Mechanical-property data from the present study are consistent with results from other investigations. The existing data have been used to establish minimum expected fracture properties for SS welds.

  2. Effects of thermal aging on fracture toughness and charpy-impact strength of stainless steel pipe welds.

    Energy Technology Data Exchange (ETDEWEB)

    Gavenda, D. J.; Michaud, W. F.; Galvin, T. M.; Burke, W. F.; Chopra, O. K.; Energy Technology

    1996-06-05

    The degradation of fracture toughness, tensile, and Charpy-impact properties of Type 308 stainless steel (SS) pipe welds due to thermal aging has been characterized at room temperature and 290 C. Thermal aging of SS welds results in moderate decreases in Charpy-impact strength and fracture toughness. For the various welds in this study, upper-shelf energy decreased by 50-80 J/cm{sup 2}. The decrease in fracture toughness J-R curve or JIC is relatively small. Thermal aging had little or no effect on the tensile strength of the welds. Fracture properties of SS welds are controlled by the distribution and morphology of second-phase particles. Failure occurs by the formation and growth of microvoids near hard inclusions; such processes are relatively insensitive to thermal aging. The ferrite phase has little or no effect on the fracture properties of the welds. Differences in fracture resistance of the welds arise from differences in the density and size of inclusions. Mechanical-property data from the present study are consistent with results from other investigations. The existing data have been used to establish minimum expected fracture properties for SS welds.

  3. Charpy impact test results of ferritic alloys from the HFIR-MFE-RB2 test

    International Nuclear Information System (INIS)

    Miniature Charpy specimens of HT-9 in base metal, weld metal and heat affected zone (HAZ) metal conditions, and 9Cr-1Mo in base metal and weld metal conditions have been tested following irradiation in HFIR-MFE-RB2 at 550C to ≅10 dpa. All specimen conditions have degraded properties (both DBTT and USE) in comparison with specimens irradiated to lower dose. 9Cr-Mo degraded more than HT-9 and weld metal performed worse than base metal which performed worse than HAZ material. Property degradation was approximately linear as a function of dose, indicating that degradation response had not saturated by 10 dpa. 6 refs., 2 figs., 2 tabs

  4. Effect of mechanical alloying atmosphere on the microstructure and Charpy impact properties of an ODS ferritic steel

    International Nuclear Information System (INIS)

    Two types of oxide dispersion strengthened (ODS) ferritic steels, with the composition of Fe-14Cr-2W-0.3Ti-0.3Y2O3 (in weight percent), have been produced by mechanically alloying elemental powders of Fe, Cr, W, and Ti with Y2O3 particles either in argon atmosphere or in hydrogen atmosphere, degassing at various temperatures, and compacting the mechanically alloyed powders by hot isostatic pressing. It was found in particular that mechanical alloying in hydrogen yields a significant reduction in oxygen content in the materials, a lower dislocation density, and a strong improvement in the fast fracture properties of the ODS ferritic steels, as measured by Charpy impact tests.

  5. Impact toughness of high strength low alloy TMT reinforcement ribbed bar

    Indian Academy of Sciences (India)

    Bimal Kumar Panigrahi; Surendra Kumar Jain

    2002-08-01

    Charpy V-notch impact toughness of 600 MPa yield stress TMT rebars alloyed with copper, phosphorus, chromium and molybdenum has been evaluated. Subsize Charpy specimens were machined from the rebar keeping the tempered martensite rim intact. The copper–phosphorus rebar showed toughness of 35 J at room temperature. The toughness of copper–molybdenum and copper–chromium rebars was 52 J. The lower toughness of phosphorus steel is attributed to solid solution strengthening and segregation of phosphorus to grain boundaries. Due to superior corrosion resistance, copper–phosphorus TMT rebar is a candidate material in the construction sector.

  6. Miniature Precracked Charpy Specimens for Measuring the Master Curve Reference Temperature of RPV Steels at Impact Loading Rates

    International Nuclear Information System (INIS)

    In the framework of the 2006 Convention, we investigated the applicability of fatigue precracked miniature Charpy specimens of KLST type (MPCC - B = 3 mm, W = 4 mm and L = 27 mm) for impact toughness measurements, using the well-characterized JRQ RPV steel. In the ductile to-brittle transition region, MPCC tests analyzed using the Master Curve approach and compared to data previously obtained from PCC specimens had shown a more ductile behavior and therefore un conservative results. In the investigation presented in this report, two additional RPV steels have been used to compare the performance of impact-tested MPCC and PCC specimens in the transition regime: the low-toughness JSPS steel and the high-toughness 20MnMoNi55 steel. The results obtained (excellent agreement for 20MnMoNi55 and considerable differences between T0 values for JSPS) are contradictory and do not presently allow qualifying the MPCC specimens as a reliable alternative to PCC samples for impact toughness measurements.

  7. Miniature Precracked Charpy Specimens for Measuring the Master Curve Reference Temperature of RPV Steels at Impact Loading Rates

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; Scibetta, M.; Puzzolante, L.

    2008-10-15

    In the framework of the 2006 Convention, we investigated the applicability of fatigue precracked miniature Charpy specimens of KLST type (MPCC - B = 3 mm, W = 4 mm and L = 27 mm) for impact toughness measurements, using the well-characterized JRQ RPV steel. In the ductile to-brittle transition region, MPCC tests analyzed using the Master Curve approach and compared to data previously obtained from PCC specimens had shown a more ductile behavior and therefore un conservative results. In the investigation presented in this report, two additional RPV steels have been used to compare the performance of impact-tested MPCC and PCC specimens in the transition regime: the low-toughness JSPS steel and the high-toughness 20MnMoNi55 steel. The results obtained (excellent agreement for 20MnMoNi55 and considerable differences between T0 values for JSPS) are contradictory and do not presently allow qualifying the MPCC specimens as a reliable alternative to PCC samples for impact toughness measurements.

  8. Effects of Oxides on Tensile and Charpy Impact Properties and Fracture Toughness in Heat Affected Zones of Oxide-Containing API X80 Linepipe Steels

    Science.gov (United States)

    Sung, Hyo Kyung; Sohn, Seok Su; Shin, Sang Yong; Oh, Kyung Shik; Lee, Sunghak

    2014-06-01

    This study is concerned with effects of complex oxides on acicular ferrite (AF) formation, tensile and Charpy impact properties, and fracture toughness in heat affected zones (HAZs) of oxide-containing API X80 linepipe steels. Three steels were fabricated by adding Mg and O2 to form oxides, and various HAZ microstructures were obtained by conducting HAZ simulation tests under different heat inputs. The no. of oxides increased with increasing amount of Mg and O2, while the volume fraction of AF present in the steel HAZs increased with increasing the no. of oxides. The strengths of the HAZ specimens were generally higher than those of the base metals because of the formation of hard microstructures of bainitic ferrite and granular bainite. When the total Charpy absorbed energy was divided into the fracture initiation and propagation energies, the fracture initiation energy was maintained constant at about 75 J at room temperature, irrespective of volume fraction of AF. The fracture propagation energy rapidly increased from 75 to 150 J and saturated when the volume fraction of AF exceeded 30 pct. At 253 K (-20 °C), the total absorbed energy increased with increasing volume fraction of AF, as the cleavage fracture was changed to the ductile fracture when the volume fraction of AF exceeded 45 pct. Thus, 45 vol pct of AF at least was needed to improve the Charpy impact energy, which could be achieved by forming a no. of oxides. The fracture toughness increased with increasing the no. of oxides because of the increased volume fraction of AF formed around oxides. The fracture toughness did not show a visible correlation with the Charpy absorbed energy at room temperature, because toughness properties obtained from these two toughness testing methods had different significations in view of fracture mechanics.

  9. Low-energy charpy impact of interleaved CF/EP laminates

    Science.gov (United States)

    Yuan, Q.; Friedrich, K.; Karger-Kocsis, J.

    1995-03-01

    Carbon fiber (CF) reinforced epoxy (CF/EP) laminates laid up in different ways (cross-ply and quasi-isotropic) with and without various adhesive interlayers (A) were studied under three-point bending using instrumented low-energy impact at single and multiple bounces. Interleaves were a modified EP resin on polyester fabric, a modified EP resin, and a polyethersulphone (PES) film. The impact response depends strongly on whether the CFs are oriented longitudinally (L) or transversely (T) to the hammer edge in the outer bounced ply. The threshold incident energy ( E in,th) associated with severe damage to the laminates was much lower with the longitudinal outer ply. The impact fatigue response of the transverse cross-ply (TCP) and quasi-isotropic (TQI) composite beams showed that stiffness degradation starts at a certain a threshold number of impact (NOI) and follows a logarithmic decay as a function of NOI. This is in close analogy to fatigue tests under usual conditions. Deterioration in stiffness can be assigned to the relative change in the secant slope ( E max/ x max) of the load-displacement ( F-x) traces. The related load-time ( F-t) traces flatten due to impact fatigue so that their load maximum ( F max) shifts toward higher contact time. The efficiency of the interleaving was assessed in both single (at E in,th≈3 J) and repeated impact (at E in=1 J). The first technique allowed us to differentiate between the various interleaves, whereas the latter contributed to finding the optimum stacking and position of the interleaves.

  10. Charpy impact test results for low activation ferritic alloys irradiated to 30 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, L.E.; Hamilton, M.L.; Gelles, D.S. [Pacific Northwest National Laboratory, Richland, WA (United States)

    1996-04-01

    Miniature specimens of six low activation ferritic alloys have been impact field tested following irradiation at 370{degrees}C to 30 dpa. Comparison of the results with those of control specimens and specimens irradiated to 10 dpa indicates that degradation in the impact behavior appears to have saturated by {approx}10 dpa in at least four of these alloys. The 7.5Cr-2W alloy referred to as GA3X appears most promising for further consideration as a candidate structural material in fusion reactor applications, although the 9Cr-1V alloy may also warrant further investigation.

  11. STRESS FIELD AT A TIP OF A PREFABRICATED SPIRAL V-NOTCH

    Institute of Scientific and Technical Information of China (English)

    郑周练; 陈山林; 叶晓明

    2004-01-01

    Based on the tranditional V-notched blasting,a technique of spirally V-notched blasting to loosen earth and rock was presented.Fracture mechanics and Westergaard stress function were adopted to build a complex stress function to derive the plane stress and strain fields at one tip of the crack under a quasi-static pressure.An expression was formulated to define the stress intensity factor of spiral V-notch loosen blasting.Factors that have effects on the stress intensity factor were studied.It is demonstrated that spiral V-notch loosen blasting is an extension of vertical V-notch blasting,straight cracking,and alike theories.

  12. Effects of Cooling Conditions on Microstructure, Tensile Properties, and Charpy Impact Toughness of Low-Carbon High-Strength Bainitic Steels

    Science.gov (United States)

    Sung, Hyo Kyung; Shin, Sang Yong; Hwang, Byoungchul; Lee, Chang Gil; Lee, Sunghak

    2013-01-01

    In this study, four low-carbon high-strength bainitic steel specimens were fabricated by varying finish cooling temperatures and cooling rates, and their tensile and Charpy impact properties were investigated. All the bainitic steel specimens consisted of acicular ferrite, granular bainite, bainitic ferrite, and martensite-austenite constituents. The specimens fabricated with higher finish cooling temperature had a lower volume fraction of martensite-austenite constituent than the specimens fabricated with lower finish cooling temperature. The fast-cooled specimens had twice the volume fraction of bainitic ferrite and consequently higher yield and tensile strengths than the slow-cooled specimens. The energy transition temperature tended to increase with increasing effective grain size or with increasing volume fraction of granular bainite. The fast-cooled specimen fabricated with high finish cooling temperature and fast cooling rate showed the lowest energy transition temperature among the four specimens because of the lowest content of coarse granular bainite. These findings indicated that Charpy impact properties as well as strength could be improved by suppressing the formation of granular bainite, despite the presence of some hard microstructural constituents such as bainitic ferrite and martensite-austenite.

  13. Charpy impact test results of ferritic alloys from the HFIR[High Flux Isotope Reactor]-MFE-RB2 test

    International Nuclear Information System (INIS)

    Miniature Charpy specimens of HT-9 in base metal, weld metal and heat affected zone (HAZ) metal conditions, and 9Cr-1Mo in base metal and weld metal conditions have been tested following irradiation in HFIR-MFE-RB2 at 550C to ≅10 dpa. All specimen conditions have degraded properties (both DBTT and USE) in comparison with specimens irradiated to lower dose. 9Cr-Mo degraded more than HT-9 and weld metal performed worse than base metal which performed worse than HAZ material. Property degradation was approximately linear as a function of dose, indicating that degradation response had not saturated by 10 dpa

  14. Impact strength of the uranium-6 weight percent niobium alloy between -1980 and +2000C

    International Nuclear Information System (INIS)

    A study was conducted to determine if a ductile-to-brittle transition wxisted for the uranium-6 wt % niobium (U-6Nb) alloy. Standard V-notched Charpy bars were made from both solution-quenched and solution-quenched and aged U-6Nb alloy and were tested between -1980 and +2000C. It was found that a sharp ductile-brittle transition does not exist for the alloy. A linear relationship existed between test temperature and impact strength, and the alloy retained a significant amount of impact strength even at very low temperatures. 9 figures

  15. Impact Behavior of A356 Foundry Alloys in the Presence of Trace Elements Ni and V

    Science.gov (United States)

    Casari, Daniele; Ludwig, Thomas H.; Merlin, Mattia; Arnberg, Lars; Garagnani, Gian Luca

    2015-02-01

    In the present work, the impact behavior of unmodified A356 alloys with the addition of Ni or V in as-cast and T6 heat-treated conditions was assessed. Charpy V-notched specimens obtained from sand and permanent mold casting showed low total absorbed energy average values ( W t sand cast alloys absorbed slightly higher impact energies compared to the corresponding A356 base alloys; (ii) in the permanent mold cast alloys, V in solid solution led to a considerable loss of ductility, which in turn decreased the total absorbed energy.

  16. Application of Instrumented Charpy Method in Characterisation of Materials

    Directory of Open Access Journals (Sweden)

    Željko Alar

    2015-07-01

    Full Text Available Testing of absorbed impact energy according to the Charpy method is carried out to determine the behaviour of a material under the impact load. Instrumented Charpy method allows getting the force displacement curve through the entire test, That curve can be related to force-displacement curve which is obtained by the static tensile test. The purpose of this study was to compare the results of forces obtained by the static tensile test with the forces obtained by the instrumented Charpy method. Experimental part of the work contains testing of the mechanical properties of S275J0 steel by the static tensile test and Impact test on instrumented Charpy pendulum.

  17. Use of precracked Charpy and smaller specimens to establish the master curve

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, M.A.; McCabe, D.E.; Nanstad, R.K. [Oak Ridge National Lab., TN (United States); Davidov, Y.A. [Institue of Metal Science, Sofia (Bulgaria)

    1997-12-01

    The current provisions used in the U.S. Code of Federal Regulations for the determination of the fracture toughness of reactor pressure vessel steels employs an assumption that there is a direct correlation between K{sub Ic} lower-bound toughness and the Charpy V-notch transition curve. Such correlations are subject to scatter from both approaches which weakens the reliability of fracture mechanics-based analyses. In this study, precracked Charpy and smaller size specimens are used in three-point static bend testing to develop fracture mechanics based K{sub k} values. The testing is performed under carefully controlled conditions such that the values can be used to predict the fracture toughness performance of large specimens. The concept of a universal transition curve (master curve) is applied. Data scatter that is characteristic of commercial grade steels and their weldments is handled by Weibull statistical modeling. The master curve is developed to describe the median K{sub Jc} fracture toughness for 1T size compact specimens. Size effects are modeled using weakest-link theory and are studied for different specimen geometries. It is shown that precracked Charpy specimens when tested within their confined validity limits follow the weakest-link size-adjustment trend and predict the fracture toughness of larger specimens. Specimens of smaller than Charpy sizes (5 mm thick) exhibit some disparities in results relative to weakest-link size adjustment prediction suggesting that application of such adjustment to very small specimens may have some limitations.

  18. Comparison of microstructural properties and Charpy impact behaviour between different plates of the Eurofer97 steel and effect of isothermal ageing

    Energy Technology Data Exchange (ETDEWEB)

    Stratil, Ludek [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Zizkova 22, 616 62 Brno (Czech Republic); Hadraba, Hynek, E-mail: hadraba@ipm.cz [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Zizkova 22, 616 62 Brno (Czech Republic); Bursik, Jiri; Dlouhy, Ivo [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Zizkova 22, 616 62 Brno (Czech Republic)

    2011-09-30

    Highlights: > Two plates of Eurofer97 steel were tested in thermally unaffected and aged state. > The two plates of Eurofer97 differ significantly in mean prior austenite grain size. > The different grain size lead to different transition temperature between the plates. > Thermal ageing applied lead to slight microstructural changes of the Eurofer97. > The microstructural changes caused small shift of transition temperature. - Abstract: The microstructure and fracture properties of the Eurofer97 steel plates of thickness 14 mm and 25 mm were investigated in as-received state and in state after long-term thermal ageing (550 deg. C/5000 h). Detailed microstructure studies were carried out by means of optical light, electron and quantitative electron microscopy. Mechanical properties were evaluated by means of Charpy impact testing and hardness testing and fracture surfaces were fractographically analysed in macro and microscales. The microstructure of the Eurofer97 consisted of tempered martensite with M{sub 23}C{sub 6} and MX precipitates. Microstructure of 14 mm plate was more homogenous and fine grained than 25 mm plate. Due to different microstructure the t{sub DBTT} of thicker plate was on +10 deg. C higher than for 14 mm plate for which reached -60 deg. C. Slight microstructural changes on the level of subgrain consisting of their partial recrystallization and slight carbide coarsening were observed after applied ageing. The isothermal ageing caused evident shift in t{sub DBTT} about +5 deg. C, which was most likely caused by recrystallization of subgrains.

  19. Degradation of impact fracture during accelerated aging of weld metal on microalloyed steel; Degradacion de la tenacidad al impacto durante el envejecimiento acelerado de soldadura en acero microaleado

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

    The effect of accelerated aging on the toughness and fracture of the longitudinal weld metal on an API5L-X52 line pipe steel was evaluated by Charpy V-notch impact test, fracture analysis and transmission electron microscopy. Aging was performed at 250 degree centigrade for 100 to 1000 h. The impact results indicated a significant reduction in the fracture energy and impact toughness as a function of aging time, which were achieved by the scanning electron microscope fractography that showed a decrease in the vol fraction of microvoids by Charpy ductile failure with the aging time, which favored the brittle fracture by transgranular cleavage. The minimum vol fraction of microvoids was reached at 500 h due to the peak aged. The microstructural analysis indicated the precipitation of transgranular iron nano carbides in the aged specimens, which was related to the deterioration of toughness and change in the ductile to brittle behavior. (Author) 15 refs.

  20. Charpy impact test results of four low activation ferritic alloys irradiated at 370{degrees}C to 15 DPA

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, L.E.; Hamilton, M.L.; Gelles, D.S. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-10-01

    Miniature CVN specimens of four low activation ferritic alloys have been impact tested following irradiation at 370{degrees}C to 15 dpa. Comparison of the results with those of control specimens indicates that degradation in the impact behavior occurs in each of these four alloys. The 9Cr-2W alloy referred to as GA3X and the similar alloy F82H with 7.8Cr-2W appear most promising for further consideration as candidate structural materials in fusion energy system applications. These two alloys exhibit a small DBTT shift to higher temperatures but show increased absorbed energy on the upper shelf.

  1. Charpy impact test results of four low activation ferritic alloys irradiated at 370 degrees C to 15 DPA

    International Nuclear Information System (INIS)

    Miniature CVN specimens of four low activation ferritic alloys have been impact tested following irradiation at 370 degrees C to 15 dpa. Comparison of the results with those of control specimens indicates that degradation in the impact behavior occurs in each of these four alloys. The 9Cr-2W alloy referred to as GA3X and the similar alloy F82H with 7.8Cr-2W appear most promising for further consideration as candidate structural materials in fusion energy system applications. These two alloys exhibit a small DBTT shift to higher temperatures but show increased absorbed energy on the upper shelf

  2. Development of dissimilar welding technique between PNC-FMS wrapper tube and SUS316 steel. 1. Investigation of δ ferrite formation and evaluation of Charpy impact property

    International Nuclear Information System (INIS)

    Ferritic/Martensitic steel (PNC-FMS) with superior resistance to swelling is being developed as wrapper tube for the long-life core of large-scale fast breeder reactor. If the δ ferrite phase would be formed at heat affected zone (HAZ) in welding between PNC-FMS wrapper tube and SUS316 steel, and thus toughness degradation would be suspected due to δ ferrite formation. In this study, the formation of the δ ferrite in applying TIG welding and EB welding are investigated using base metal of 3 types, which are Nieq max./Creq min., Nieq min./Creq max. and the center of chemical composition in the specification. The effect of the amount of the δ ferrite formation and characteristics of toughness change with thermal aging were evaluated. The results are summarized as follows. 1. The δ ferrite generation can be suppressed in the combination of welding process and chemical composition. (1) In case of specification center, the δ ferrite formation can be suppressed about 1% by EB welding. (2) In case of Nieq max./Creq min. in the specification, the δ ferrite formation can be perfectly suppressed even in TIG welding or EB welding. 2. The relationship between δ ferrite content and Charpy impact value was investigated using 3 types of chemical composition in the specification. (1) Ductile Brittle Transition Temperature (DBTT) increased, when δ ferrite content increases. (2) DBTT shift by aging is within about 23degC. (3) DBTT is influenced by grain size and it is lower as the fine grain (grain no.11). (4) Upper Shelf Energy (USE) is not dependent on the δ ferrite content. (author)

  3. Further Charpy impact test results of low activation ferritic alloys, irradiated at 430{degrees}C to 67 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, L.E.; Hamilton, M.L.; Gelles, D.S. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-04-01

    Miniature CVN specimens of four ferritic alloys, GA3X, F82H, GA4X and HT9, have been impact tested following irradiation at 430{degrees}C to 67 dpa. Comparison of the results with those of the previously tested lower dose irradiation condition indicates that the GA3X and F82H alloys, two primary candidate low activation alloys, exhibit virtually identical behavior following irradiation at 430{degrees}C to {approximately}67 dpa and at 370{degrees}C to {approximately}15 dpa. Very little shift is observed in either DBTT or USE relative to the unirradiated condition. The shifts in DBTT and USE observed in both GA4X and HT9 were smaller after irradiation at 430{degrees}C to {approximately}67 dpa than after irradiation at 370{degrees}C to {approximately}15 dpa.

  4. Instrumented impact testing machine with reduced specimen oscillation effects

    International Nuclear Information System (INIS)

    Owing to small and inexpensive specimens the Charpy impact test is widely used in quality control and alloy development. Limitations in power reactor survellance capsules it is also widely used for safety analysis purposes. Instrumenting the tup and computerizing data acquisition, makes dynamic fracture mechanics data measurement possible and convenient. However, the dynamic effects (inertia forces, specimen oscillations) in the impact test cause inaccuracies in the recorded load-time diagram and hence diminish the reliability of the calculated dynamic fracture mechanics parameters. To decrease inaccuracies a new pendulum type of instrumented impact test apparatus has been developed and constructed in the Metals Laboratory of the Technical Research Centre of Finland. This tester is based on a new principle involving inverted test geometry. The purpose of the geometry inversion is to reduce inertia load and specimen oscillation effects. Further, the new impact tester has some other novel features: e.g. the available initia impact energy is about double compared to the conventional standard (300 J) impact tester allowing the use of larger (10 x 20 x 110 mm) bend specimens than normal Charpy specimens. Also, the rotation asix in the three point bending is nearly stationary making COD-measurements possible. An experimental test series is described in which the inertia effects and specimen oscillations are compared in the conventional and new impact tester utilizing Charpy V-notch specimens. Comparison of the two test geometries is also made with the aid of an analytical model using finite element method (FEM) analysis. (author)

  5. Evaluation of impact properties of weld joint of reactor pressure vessel steels with the use of miniaturized specimens

    International Nuclear Information System (INIS)

    The effects of specimen size and location of V-notch on the Charpy impact properties were investigated with different sizes of specimens, standard, CVN-1/2, CVN-1/3, and CVN-1.5 mm, for A533B steel, low Mn, high Cu, high phosphorus (P), and high Cu/P steel weld joint. A part of the specimens was irradiated with neutron at 563 K up to 8x1019 n/cm2. The heat affected zone (HAZ) specimen is the best in the impact properties among the specimens of base metal, HAZ, and weld metal in the steels with 0.003 wt.% P, while it is the worst in the steels with ∼ 0.3 wt.% P. This indicates that the surveillance test of HAZ specimen can be represented by base metal in the case of A533B steels with lower P content (∼ 0.003 wt.%). The effects of notch location and chemical contents on ductile to brittle transition temperature (DBTT) are almost independent of specimen size within an error of ±5 K, indicating that the miniaturized Charpy specimens are applicable and effective in the surveillance tests of reactor pressure vessel steel of extended operation period. After irradiation, the highest DBTT was observed for the specimen with V-notch in base metal in the case of A533B steel and high Cu steel with 0.003 wt.% P. (author)

  6. Tensile and Charpy impact properties of an ODS ferritic/martensitic steel 9Cr–1.8W–0.5Ti–0.35Y2O3

    International Nuclear Information System (INIS)

    Highlights: • The tensile property and Charpy impact were tested. • Both strength and plasticity in LT direction are better than that of TL direction. • The LSE was more than 65% of the USE from absorbed energy curve. • The initiation and propagation energy at different temperatures were calculated. • High LSE and dimples on the fracture surface indicated good toughness at −60 °C. - Abstract: A 9Cr-ODS ferritic/martensitic steel with a composition of 9Cr–1.8W–0.5Ti–0.35Y2O3 was fabricated by mechanical alloying and hot isostatic pressing, followed by hot rolling. Tensile properties were measured at room temperature (23 °C) and 700 °C in the rolling direction (LT) and the transverse direction (TL). The ultimate tensile strength (UTS) of the as-rolled samples in both directions reached 990 MPa at 23 °C, and still maintained at 260 MPa at 700 °C. The tensile strength and elongation of the rolling direction was greater than that of the transverse direction. The Charpy impact was tested from −100 to 100 °C in the LT direction. The lower shelf energy (LSE) was more than 65% of the upper shelf energy (USE). The total absorbed energy was separated into the energies for crack initiation and propagation. The propagation energy was always higher than the initiation energy in the range of temperatures tested. The ductile-to-brittle transition temperature (DBTT) of the rolled 9Cr ODS evaluated by an absorbed energy curve was about 0 °C. However, the high LSE and the fracture surface that still contained dimples at lower shelf indicated good toughness of the as-rolled 9Cr ODS steels at temperature of −60 °C

  7. Tensile and Charpy impact properties of an ODS ferritic/martensitic steel 9Cr–1.8W–0.5Ti–0.35Y{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guangming; Zhou, Zhangjian, E-mail: zhouzhj@mater.ustb.edu.cn; Wang, Man; Li, Shaofu; Zou, Lei; Zhang, Liwei

    2014-04-15

    Highlights: • The tensile property and Charpy impact were tested. • Both strength and plasticity in LT direction are better than that of TL direction. • The LSE was more than 65% of the USE from absorbed energy curve. • The initiation and propagation energy at different temperatures were calculated. • High LSE and dimples on the fracture surface indicated good toughness at −60 °C. - Abstract: A 9Cr-ODS ferritic/martensitic steel with a composition of 9Cr–1.8W–0.5Ti–0.35Y{sub 2}O{sub 3} was fabricated by mechanical alloying and hot isostatic pressing, followed by hot rolling. Tensile properties were measured at room temperature (23 °C) and 700 °C in the rolling direction (LT) and the transverse direction (TL). The ultimate tensile strength (UTS) of the as-rolled samples in both directions reached 990 MPa at 23 °C, and still maintained at 260 MPa at 700 °C. The tensile strength and elongation of the rolling direction was greater than that of the transverse direction. The Charpy impact was tested from −100 to 100 °C in the LT direction. The lower shelf energy (LSE) was more than 65% of the upper shelf energy (USE). The total absorbed energy was separated into the energies for crack initiation and propagation. The propagation energy was always higher than the initiation energy in the range of temperatures tested. The ductile-to-brittle transition temperature (DBTT) of the rolled 9Cr ODS evaluated by an absorbed energy curve was about 0 °C. However, the high LSE and the fracture surface that still contained dimples at lower shelf indicated good toughness of the as-rolled 9Cr ODS steels at temperature of −60 °C.

  8. Static and impact crack properties of a high-strength steel welded joint

    Energy Technology Data Exchange (ETDEWEB)

    Zrilic, M. [Faculty of Technology and Metallurgy, Karnegijeva 4, 11000 Belgrade (Serbia)]. E-mail: misa@tmf.bg.ac.yu; Grabulov, V. [Military Technical Institute, Ratka Resanovica 1, Belgrade (Serbia); Burzic, Z. [Military Technical Institute, Ratka Resanovica 1, Belgrade (Serbia); Arsic, M. [Institute for Material Testing, Bul. Vojvode Misica 43, Belgrade (Serbia); Sedmak, S. [Faculty of Technology and Metallurgy, Karnegijeva 4, 11000 Belgrade (Serbia)

    2007-03-15

    In order to gain the benefits of weldable high-strength steels in pressurized equipment applications, satisfactory toughness and crack properties of the welded joint, both in the weld metal and the heat-affected -zone (HAZ), are required. Experimental investigations of toughness and crack resistance parameters through static and impact tests of a high-strength, low-alloy steel (HSLA) with a nominal yield strength of 700 MPa and its welded joint, were performed on Charpy-sized specimens, V-notched and pre-cracked, of the parent metal, weld metal and HAZ. The selected electrode produced slight undermatching and enabled the welded joints to be manufactured without cold cracks. The impact energy and its parts responsible for crack initiation and propagation were determined by toughness evaluation. Crack sensitivity, defined as the ratio of the impact energy for V-notched and for pre-cracked specimens, enabled a comparison of the homogeneous microstructure of the parent metal and the weld metal, and of the heterogeneous microstructure of the heat-affected-zone (HAZ), which indicated a better crack toughness behaviour of the HAZ. The results obtained showed that the toughness and crack resistance of the weld metal were significantly lower than those of the parent metal and the HAZ. The fracture mechanics parameters, J {sub Ic} integral, and plane strain fracture toughness, K {sub Ic}, as well as J resistance curves expressed the degradation less.

  9. Effect of V Notch Shape on Fatigue Life in Steel Beam Made of AISI 1037

    Directory of Open Access Journals (Sweden)

    Qasim Bader

    2014-04-01

    Full Text Available The present work encompasses effect of V notch shape with various geometries and dimensions on fatigue life behavior in steel beam made of Medium Carbon Steel AISI 1037 which has a wide application in industry. Fatigue life of notched specimens is calculated using the fatigue life obtained from the experiments for smooth specimens (reference and by use Numerical method (FEA.The fatigue experiments were carried out at room temperature, applying a fully reversed cyclic load with the frequency of (50Hz and mean stress equal to zero (R= -1, on a cantilever rotating-bending fatigue testing machine. The stress ratio was kept constant throughout the experiment. Different instruments have been used in this investigation like Chemical composition analyzer type (Spectromax ,Tensile universal testing machine type (WDW-100E ,Hardness tester type (HSV- 1000 , Fatigue testing machine model Gunt WP 140, Optical Light Microscope (OLM and Scanning Electron Microscope (SEM were employed to examine the fracture features . The results show that there is acceptable error between experimental and numerical works .

  10. METHOD TO CALCULATE STRESS INTENSITY FACTOR OF V-NOTCH IN BI-MATERIALS

    Institute of Scientific and Technical Information of China (English)

    Youtang Li; Ming Song

    2008-01-01

    Based on Zak's stress function,the eigen-equation of stress singularity of bi-materials with a Ⅴ-notch was obtained.A new definition of stress intensity factor for a perpendicular inter facial Ⅴ-notch of bi-material was put forward.The effects of shear modulus and Poisson's ratio of the matrix material and attaching material on eigen-values were analyzed.A generalized ex pression for calculating KI of the perpendicular V-notch of bi-materials was obtained by means of stress extrapolation.Effects of notch depth,notch angle and Poisson's ratio of materials on the singular stress field near the tip of the Ⅴ-notch were analyzed systematically with numerical simulations.As an example,a finite plate with double edge notches under uniaxial uniform ten sion was calculated by the method presented and the influence of the notch angle and Poisson's ratio on the stress singularity near the tip of notch was obtained.

  11. Failure mechanics of fiber composite notched charpy specimens. [stress analysis

    Science.gov (United States)

    Chamis, C. C.

    1976-01-01

    A finite element stress analysis was performed to determine the stress variation in the vicinity of the notch and far field of fiber composites Charpy specimens (ASTM Standard). NASTRAN was used for the finite element analysis assuming linear behavior and equivalent static load. The unidirectional composites investigated ranged from Thornel 75 Epoxy to S-Glass/Epoxy with the fiber direction parallel to the long dimension of the specimen. The results indicate a biaxial stress state exists in (1) the notch vicinity which is dominated by transverse tensile and interlaminar shear and (2) near the load application point which is dominated by transverse compression and interlaminar shear. The results also lead to the postulation of hypotheses for the predominant failure modes, the fracture initiation, and the fracture process. Finally, the results indicate that the notched Charpy test specimen is not suitable for assessing the impact resistance of nonmetallic fiber composites directly.

  12. Transferability of Charpy Absorbed Energy to Fracture Toughness Based on Weibull Stress Criterion

    Institute of Scientific and Technical Information of China (English)

    Hongyang JING; Lianyong XU; Lixing HUO; Fumiyoshi Minami

    2005-01-01

    The relationship between Charpy absorbed energy and the fracture toughness by means of the (crack tip opening displacement (CTOD)) method was analyzed based on the Weibull stress criterion. The Charpy absorbed energy and the fracture toughness were measured for the SN490B steel under the ductile-brittle transition temperature region. For the instrumented Charpy impact test, the curves between the loading point displacement and the load against time were recorded. The critical Weibull stress was taken as a fracture controlled parameter, and it could not be affected by the specimen configuration and the loading pattern based on the local approach. The parameters controlled brittle fracture are obtained from the Charpy absorbed energy results, then the fracture toughness for the compact tension (CT) specimen is predicted. It is found that the results predicted are in good agreement with the experimental. The fracture toughness could be evaluated by the Charpy absorbed energy, because the local approach gives a good description for the brittle fracture even though the Charpy impact specimen or the CT specimen is used for the given material.

  13. 系列冲击试验转变温度的意义及其局限性%Significance and limitations of transition temperature based on series Charpy impact tests

    Institute of Scientific and Technical Information of China (English)

    马伟; 姜自强; 姜安婕

    2011-01-01

    文章采用双曲正切函数模型,对夏比冲击试验转变温度曲线的数学特征和各种定义的转变温度的物理意义进行了分析探讨,明确了以转变温度曲线比较材料低温韧性的2个基本原则,提出指标转变温度的相对性概念和相对指标转变温度定义的严重缺陷,在重要场合,应以2种以上类型的转变温度予以验证,ASTME185给出的方法值得借鉴.%Mathematical characteristics of transition temperature curve and physical significance of several definitions of transition temperature based on Charpy impact tests are analyzed by using the hyperbolic tangent function model. Two principles in comparing low temperature toughness of materials in light of transition temperature curve are proposed. The relativity of temperature transition indexes is discussed and the limitations of the definition of the relative temperature transition indexes is pointed out. In some important situations, verification should be carried out based on two or more types of transition temperature and the method given by ASTM E185 is useful.

  14. Charpy V, an application in Mat lab

    International Nuclear Information System (INIS)

    The obtained results with the system Charpy VV1 designed in Mat lab for the estimate of parameters of three mathematical models are shown. The adjustment of data is used to determine the fracture energy, the lateral expansion and the percentage of ductility of steels coming from the reactor vessels of Laguna Verde, Veracruz. The data come from test tubes type Charpy V of irradiated material and not irradiated. To verify our results they were compared with those obtained by General Electric of data coming from the Laguna Verde nuclear power plant. (Author)

  15. Study of crack propagation mechanisms during Charpy impact toughness tests on both equiaxed and lamellar microstructures of Ti–6Al–4V titanium alloy

    International Nuclear Information System (INIS)

    The impact toughness of two highly textured rolled plates of Ti–6Al–4V alloy with an α equiaxed and an α lamellar microstructures has been investigated. The results show a strong anisotropy of the fracture energy for both materials and underline that a coincidence of the prismatic planes with the shear bands at the notch tip is favorable for higher fracture energies. Moreover, it is pointed out, as it was already done by previous studies, that the α lamellar microstructure presents higher fracture energy than the α equiaxed one. Thanks to electron back scattering diffraction, and tensile tests, local microstructure heterogeneities, called macrozones, have been observed and characterized. Their size depends on microstructure element and is larger for α lamellar microstructure than for the α equiaxed. High strain is localized on the macrozones favorably oriented for prismatic slip with respect to the direction of impact and leads to a particular dimple free zone on the fracture surface. The contribution of these macrozones in the fracture behavior, and more precisely on the crack propagation rate was evaluated; thus the effects of the macroscopic texture and of the microstructure element on the impact toughness are discussed separately

  16. Study of crack propagation mechanisms during Charpy impact toughness tests on both equiaxed and lamellar microstructures of Ti–6Al–4V titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Buirette, Christophe, E-mail: christophe.buirette@ensiacet.fr [Institut Carnot CIRIMAT, ENSIACET, 4 allée Emile Monso, 31030 Toulouse (France); Huez, Julitte, E-mail: julitte.huez@ensiacet.fr [Institut Carnot CIRIMAT, ENSIACET, 4 allée Emile Monso, 31030 Toulouse (France); Gey, Nathalie, E-mail: Nathalie.gey@univ-lorraine.fr [Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR CNRS 7239, Université de Lorraine, Île du Saulcy, 57045 METZ Cedex 1 (France); DAMAS, Laboratory of Excellence on Design of Alloy Metals for Low-Mass Structures, Université de Lorraine (France); Vassel, Alain, E-mail: alain.vassel@titane.asso.fr [Association Française du Titane, 16 quai Ernest Renaud, BP 70515, 44105 Nantes Cedex 4 (France); Andrieu, Eric, E-mail: eric.andrieu@ensiacet.fr [Institut Carnot CIRIMAT, ENSIACET, 4 allée Emile Monso, 31030 Toulouse (France)

    2014-11-17

    The impact toughness of two highly textured rolled plates of Ti–6Al–4V alloy with an α equiaxed and an α lamellar microstructures has been investigated. The results show a strong anisotropy of the fracture energy for both materials and underline that a coincidence of the prismatic planes with the shear bands at the notch tip is favorable for higher fracture energies. Moreover, it is pointed out, as it was already done by previous studies, that the α lamellar microstructure presents higher fracture energy than the α equiaxed one. Thanks to electron back scattering diffraction, and tensile tests, local microstructure heterogeneities, called macrozones, have been observed and characterized. Their size depends on microstructure element and is larger for α lamellar microstructure than for the α equiaxed. High strain is localized on the macrozones favorably oriented for prismatic slip with respect to the direction of impact and leads to a particular dimple free zone on the fracture surface. The contribution of these macrozones in the fracture behavior, and more precisely on the crack propagation rate was evaluated; thus the effects of the macroscopic texture and of the microstructure element on the impact toughness are discussed separately.

  17. Charpy V, an application in Mat lab; Charpy V, una aplicacion en Matlab

    Energy Technology Data Exchange (ETDEWEB)

    Castillo M, J.A.; Torres V, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    The obtained results with the system Charpy V{sub V}1 designed in Mat lab for the estimate of parameters of three mathematical models are shown. The adjustment of data is used to determine the fracture energy, the lateral expansion and the percentage of ductility of steels coming from the reactor vessels of Laguna Verde, Veracruz. The data come from test tubes type Charpy V of irradiated material and not irradiated. To verify our results they were compared with those obtained by General Electric of data coming from the Laguna Verde nuclear power plant. (Author)

  18. Evaluation of fracture toughness in dental ceramics using indentation and SEVNB (Single Edge V-Notched Beam)-method

    International Nuclear Information System (INIS)

    In this work, the fracture toughness of different ceramics based on Al2O3 and ZrO2 were evaluated using, comparatively two methods, Vickers indentation and SEVNB (Single Edge V-Notched Beam) method. Al2O3, ZrO2(3%Y2O3) micro-particled and ZrO2(3%Y2O3) nanometric, ZrO2-Al2O3 and Al2O3-ZrO2 composites were sintered at different temperatures. Samples were characterized by relative density, X-ray diffraction, SEM, and mechanical evaluation by hardness, bending strength and fracture toughness obtained by ickers indentation and SEVNB-method. The results were presented comparing the densification and microstructural results. Furthermore, the advantages and limitations of each method were discussed. (author)

  19. Estimation of Charpy notch toughness for thermal aging specimens of cast duplex stainless steel using thermalelectric power measurement

    International Nuclear Information System (INIS)

    The material properties of cast duplex stainless steel, which is used for main coolant pipes of PWR (pressurized water reactor) type nuclear power plants, change due to thermal aging. Therefore it is advisable to evaluate these changes of material properties non-destructively for maintenance of the plant component. In order to establish a non-destructive evaluation procedure for the degree of thermal aging of cast duplex stainless steel, thermoelectric power (TEP) measurements were carried out with a newly made TEP meter for thermal aging specimens, with different ferrite contents, aging temperatures and aging periods. Then the relationship between TEP and notch toughness obtained by Charpy impact test was investigated. As the results: (1) TEP increases due to thermal aging. The higher ferrite content, the higher TEP. The higher aging temperature, the more rapidly TEP increases. (2) Because of the decrease of Charpy notch toughness and the increase of TEP due to the fluctuation of Cr concentration caused by the phase separation of the ferrite phase, TEP increases by thermal aging as the Charpy notch toughness decreases. (3) Regardless of the aging temperature, the specimens with the same ferrite content have the same relationship between Charpy notch toughness and TEP. (4) It is possible to estimate Charpy notch toughness with an error of 100 J/cm2 by TEP in the beginning of aging. Therefore, it can be concluded that we can estimate Charpy notch toughness for cast duplex stainless steel by TEP depending on the ferrite content regardless of the aging temperature. (author)

  20. Electron beam welding reconstitution technology of Charpy-V specimens

    International Nuclear Information System (INIS)

    This paper reports results connected with the reconstitution of the Cv-type specimens by electron beam welding technology. The experiments were carried out using a 15 kW Leybold Heraus welding unit in a range of power between 1.5 and 3.5 kW, and welding speed from 0.5cm/s to 1.5 cm/s. Material which used in this study is 15Kh2NMFA reactor pressure vessel steel. Weldability of pressure vessel steel by electron beam was investigated in accordance EN ISO 13919-1 1996. Charpy impact tests show good agreement between original and electron beam reconstituted specimens. (author)

  1. Evaluation of fracture toughness in dental ceramics using indentation and SEVNB (Single Edge V-Notched Beam)-method; Avaliacao da tenacidade a fratura de ceramicas dentarias atraves do metodo de entalhe - SEVNB (Single Edge V-Notched Beam)

    Energy Technology Data Exchange (ETDEWEB)

    Santos, L.A.; Santos, C.; Souza, R.C.; Ribeiro, S. [Universidade de Sao Paulo (DEMAR/EEL/USP), Lorena, SP (Brazil). Escola de Engenharia de Lorena. Dept. de Engenharia de Materiais. Polo Urbo-Industrial; Strecker, K. [Universidade Federal de Sao Joao del-Rei (DME/UFSJ), MG (Brazil). Dept. de Materiais Eletricos; Oberacker, R. [Karlsruhe Univ. (Germany)

    2009-07-01

    In this work, the fracture toughness of different ceramics based on Al{sub 2}O{sub 3} and ZrO{sub 2} were evaluated using, comparatively two methods, Vickers indentation and SEVNB (Single Edge V-Notched Beam) method. Al{sub 2}O{sub 3}, ZrO{sub 2}(3%Y{sub 2}O{sub 3}) micro-particled and ZrO{sub 2}(3%Y{sub 2}O{sub 3}) nanometric, ZrO{sub 2}-Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-ZrO{sub 2} composites were sintered at different temperatures. Samples were characterized by relative density, X-ray diffraction, SEM, and mechanical evaluation by hardness, bending strength and fracture toughness obtained by ickers indentation and SEVNB-method. The results were presented comparing the densification and microstructural results. Furthermore, the advantages and limitations of each method were discussed. (author)

  2. Effects of Notch Location on Heat-affected Zone Impact Properties of SA-516 Steels

    Science.gov (United States)

    Hong, Jaekeun; Park, Jihong; Kang, Chungyun

    In case of welding for pressure retaining parts on nuclear components, the verifications of heat affected zone (HAZ) impact properties are required according to application codes such as ASME Sec. III, RCC-M, KEPIC (Korea Electric Power Industry Code) MN, and JEA (Japan Electric Association) Code. Especially in case of Charpy V-notch tests of HAZ, the requirements of notch location and specimen direction have greatly impact on the reliability and consistency of the test results. For the establishment of newly adequate impact test requirements, the requirements about the HAZ impact tests of ASME Section III, RCC-M, KEPIC MN and JEA code were researched in this study. And also the HAZ impact test requirements about surveillance tests in nuclear reactor vessels were compared and investigated. For the effects of the notch location and specimen direction on the impact properties, SA-516 Gr.70 materials were investigated. The specimens were fabricated with using shielded metal-arc welding, and maximum heat inputs were controlled within the range of 16˜27 kJ/cm. Especially, this research showed the lateral expansion values and absorbed energies were not compatible and the impact test results were varied depending on notch location and specimen direction. Based on this study, newly adequate impact test requirements of HAZ were proposed.

  3. Correlations between Standard and Miniaturised Charpy-V Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; Van Walle, E.; Fabry, A.; Puzzolante, J.-L.; Verstrepen, A.; Vosch, R.; Van de Velde, L

    1998-12-01

    A total of 565 instrumented impact tests (232 performed on full-size and 333 on sub-size Charpy-V specimens) have been analysed in order to derive meaningful assumptions on the correlations existing between test results obtained on specimens of different size. Nine materials (pressure vessel steels) have been considered, in both as-received and irradiated state, for a total of 19 conditions examined. For the analysis of data, conventional as well novel approaches have been investigated; former ones, based on a review of the existing literature, include predictions of USE values by the use of normalization factors (NF), shifts of index temperatures related to energy/lateral expansion/shear fracture levels, and a combination of both approaches (scaling and shifting of energy curves). More original and recent proposals have also been verified, available in the literature but also proposed by SCK-CEN in the frame of enhanced surveillance of nuclear reactor pressure vessels. Conclusions have been drawn regarding the applicability and reliability of these methodologies, and recommendations have been given for future developments of the activities on this topic.

  4. On the Effectiveness of the Dynamic Force Adjustment for Reducing the Scatter of Instrumented Charpy Results

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.

    2008-09-15

    One of the key factors for obtaining reliable instrumented Charpy results is the calibration of the instrumented striker. An interesting alternative to the conventional static calibration recommended by the standards is the Dynamic Force Adjustment (DFA), in which forces and displacements are iteratively adjusted until equality is achieved between absorbed energies calculated under the test record (Wt) and measured by the machine encoder (KV). In this study, this procedure has been applied to the instrumented data obtained by 10 international laboratories using notched and precracked Charpy specimens, in the framework of a Coordinated Research Project (CRP8) of IAEA. DFA is extremely effective in reducing the between-laboratory scatter for both general yield and maximum forces. The effect is less significant for dynamic reference temperatures measured from precracked Charpy specimens using the Master Curve procedure, but a moderate reduction of the standard deviation is anyway observed. It is shown that striker calibration is a prominent contribution to the interlaboratory variability of instrumented impact forces, particularly in the case of maximum forces.

  5. Impact Behavior of A356 Foundry Alloys in the Presence of Trace Elements Ni and V

    Science.gov (United States)

    Casari, Daniele; Ludwig, Thomas H.; Merlin, Mattia; Arnberg, Lars; Garagnani, Gian Luca

    2015-02-01

    In the present work, the impact behavior of unmodified A356 alloys with the addition of Ni or V in as-cast and T6 heat-treated conditions was assessed. Charpy V-notched specimens obtained from sand and permanent mold casting showed low total absorbed energy average values ( W t < 2 J). SEM analysis of fracture profiles and surfaces indicated a Si-driven crack propagation with a predominant transgranular fracture mode. Occasionally, intergranular contributions to fracture were detected in the permanent mold cast alloys due to the locally finer microstructure. Concurrent mechanisms related to the chemical composition, solidification conditions and heat treatment were found to control the impact properties of the alloys. While the trace element Ni exerted only minor effects on the impact toughness of the A356 alloy, V had a strong influence: (i) V-containing sand cast alloys absorbed slightly higher impact energies compared to the corresponding A356 base alloys; (ii) in the permanent mold cast alloys, V in solid solution led to a considerable loss of ductility, which in turn decreased the total absorbed energy.

  6. Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel

    International Nuclear Information System (INIS)

    In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 °C and tempering at 750 °C, while the HAZs consisted of martensite, δ-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and δ-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the δ-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the δ-ferrite remained in the tempered HAZs

  7. Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel

    Science.gov (United States)

    Moon, Joonoh; Lee, Chang-Hoon; Lee, Tae-Ho; Jang, Min-Ho; Park, Min-Gu; Han, Heung Nam

    2014-12-01

    In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 °C and tempering at 750 °C, while the HAZs consisted of martensite, δ-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and δ-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the δ-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the δ-ferrite remained in the tempered HAZs.

  8. Determination of anisotropy in impact toughness of aluminium alloy 2024 T3 plate

    Science.gov (United States)

    Siddiqui, M. H.; Hashmi, F.; Junaid, A.

    The research was aimed to quantify the existence of anisotropy in fracture toughness of aluminium alloy 2024 T3 plate (used in aircraft structural members). It was further needed to establish the direction in which the fracture toughness of aluminium alloy 2024 T3 plate is maximum and minimum. This could help ascertain the structural integrity of aircraft structural components; also while designing new components, the knowledge of variation in toughness with respect to direction helps in economizing dead weight of the aircraft. In this research, pursued at the College of Aeronautical Engineering, the anisotropy in toughness of aluminium alloy 2024 T3 plate was analysed using the Charpy V-notch impact toughness test. The effect of specimen orientation on the impact toughness values of the alloy was investigated and compared with known results to verify the reliability of the work and to ascertain the extent of anisotropy in fracture toughness of the said alloy. Charpy impact tests were carried out on ASTM E 23 standard specimens machined at a reference laboratory at room temperature (23° C +/- 2° C). Four different specimen orientations analysed for the purpose of this study were L-S, L-T, T-S and T-L directions. Subsequently, the results obtained at the research centre were then analysed and correlated with morphology of microstructure of the material to establish the reliability of the experimental results. Moreover, an analysis was also done to cater for the possible errors that could affect the fracture toughness values obtained from experimental results. It was concluded that the T-S orientation of the plate had maximum toughness, whereas, minimum toughness was observed in L-T direction.

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

    International Nuclear Information System (INIS)

    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.

  10. Tensile and impact behaviour of a microalloyed medium carbon steel: Effect of the cooling condition and corresponding microstructure

    International Nuclear Information System (INIS)

    Highlights: ► Effect of different cooling rate after hot rolling in medium C microalloyed steels. ► Effect of microstructure on the impact toughness, at room and sub-zero temperatures. ► Brittle behavior induced by the fracture of large (Ti, V)(C, N) inclusions. ► Acicular ferrite deflects propagation cracks increasing impact toughness. -- Abstract: The effect of cooling rate after hot rolling on the final microstructure and mechanical properties of a microalloyed medium C steel was investigated. The microstructure was characterized by optical microscopy; the mechanical behavior was studied by hardness, tensile and instrumented Charpy V-notch impact tests carried out at room and sub-zero temperatures. The results of microstructural analysis indicate that a low cooling rate of 0.7 °C/s led to a mixed microstructure consisting of perlite, pro-eutectoid ferrite and bainite, while an increase of the cooling rate to 7.5 °C/s favored the formation of martensite and acicular ferrite. This latter microstructure, in turn, induced an increase in the tensile strength of the steel, with a reduction of its elongation to failure, and superior impact toughness. Analyses of the fracture surfaces with scanning electron microscopy confirmed the influence of the two microstructures on the failure mechanisms of the steel.

  11. Comparison of transition temperature criteria applied for KLST and ISO-V type Charpy specimens

    International Nuclear Information System (INIS)

    A great deal of test data have been obtained on reactor pressure vessel steels using the standard Charpy-V test. Although more advanced test methods, based on elastic-plastic fracture mechanics, are both recommendable and already in use in the surveillance programmes of some nuclear power plants (NPPs), Charpy tests are still required, e.g., by regulatory guides. Besides the normal-size (ISO-V) Charpy specimen (10 x10 x 55 mm3), various types of sub-size specimens have been introduced. One standardised sub-size specimen being in use is the so-called KLST specimen, the size of which is 3 x 4 x 27 mm3 with 1 mm central notch (DIN50 115). So far the test data published for the KLST specimen, as well as sub-size specimens in general, is still limited. The results from small specimen testing are typically used for evaluating the fracture behaviour of the ISO-V Charpy specimen and if there are no test results available for the correlation, as there usually is not, a general correlation has to be applied to evaluate the fracture behaviour of the ISO-V specimen. The availability of a sub-size specimen depends therefore significantly on how reliably this relationship has been established. Impact test data measured with different specimens have been correlated using some appropriate criterion (or criteria) and since a total transition curve is normally measured, there are several ones available. The criterion can be a fixed energy or lateral expansion level describing the transition temperature or the level can be derived from the upper-shelf energy (USE). In general, the proposed criterion can be divided into two groups: those derived from the dimensions of the specimens and those derived empirically from experimental data. Test data measured with ISO-V and KLST-type Charpy specimens are discussed and the validity of two proposed, basically different transition temperature criteria and the resulting differences in the temperatures, that are inevitable because of the

  12. Influence of Striking Edge Radius (2 mm versus 8 mm) on Instrumented Charpy Data and Absorbed Energies

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.

    2008-08-15

    The most commonly used test standards for performing Charpy impact tests (ISO 148 and ASTM E 23) envisage the use of strikers having different radii of the striking edge, i.e. 2 mm (ISO) and 8 mm (ASTM). The effect of striker geometry on Charpy results was extensively studied in the past in terms of absorbed energy measured by the machine encoder, but few investigations are available on the influence of striker configuration on the results of instrumented Charpy tests (characteristic forces, displacements and integrated energy). In this paper, these effects are investigated based on the analysis of published results from three interlaboratory studies and some unpublished Charpy data obtained at SCK-CEN. The instrumented variables which are the most sensitive to the radius of the striking edge are the maximum force and its corresponding displacement, with 8mm-strikers providing systematically higher values. Absorbed energies, obtained both from the instrumented trace and from the pendulum encoder, are almost insensitive to the type of striker up to 200 J. For higher energy levels, the values obtained from 8mm strikers become progressively larger. Data scatter is generally higher for 2mm-strikers.

  13. Effects of Notch Misalignment and Tip Radius on Displacement Field in V-Notch Rail Shear Test as Determined by Photogrammetry

    Science.gov (United States)

    Hill, Charles S.; Oliveras, Ovidio M.

    2011-01-01

    Evolution of the 3D strain field during ASTM-D-7078 v-notch rail shear tests on 8-ply quasi-isotropic carbon fiber/epoxy laminates was determined by optical photogrammetry using an ARAMIS system. Specimens having non-optimal geometry and minor discrepancies in dimensional tolerances were shown to display non-symmetry and/or stress concentration in the vicinity of the notch relative to a specimen meeting the requirements of the standard, but resulting shear strength and modulus values remained within acceptable bounds of standard deviation. Based on these results, and reported difficulty machining specimens to the required tolerances using available methods, it is suggested that a parametric study combining analytical methods and experiment may provide rationale to increase the tolerances on some specimen dimensions, reducing machining costs, increasing the proportion of acceptable results, and enabling a wider adoption of the test method.

  14. Experimental Investigation of Charpy Impact Tests on Metallic SLM parts

    OpenAIRE

    Yasa, Evren; Deckers, Jan; Kruth, Jean-Pierre; Rombouts, Marleen; Luyten, Jan

    2009-01-01

    Selective laser melting (SLM) is a layer-additive manufacturing technology making it possible to create fully functional parts directly from standard metal powders without using any intermediate binders or any additional post-processing steps. During the process, a laser source selectively scans a powder bed according to the CAD data of the part to be produced and powder particles are completely molten by a high intensity laser beam. SLM is capable of producing near full density metallic part...

  15. Fractographic examination of reduced activation ferritic/martensitic steel charpy specimens irradiated to 30 dpa at 370{degrees}C

    Energy Technology Data Exchange (ETDEWEB)

    Gelles, D.S.; Hamilton, M.L. [Pacific Northwest National Lab., Richland, WA (United States); Schubert, L.E. [Univ. of Missouri, Rolla, MO (United States)

    1996-10-01

    Fractographic examinations are reported for a series of reduced activation ferritic/Martensitic steel Charpy impact specimens tested following irradiation to 30 dpa at 370{degrees}C in FFTF. One-third size specimens of six low activation steels developed for potential application as structural materials in fusion reactors were examined. A shift in brittle fracture appearance from cleavage to grain boundary failure was noted with increasing manganese content. The results are interpreted in light of transmutation induced composition changes in a fusion environment.

  16. Standard Guide for Reconstitution of Irradiated Charpy-Sized Specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This guide covers procedures for the reconstitution of ferritic pressure boundary steels used in nuclear power plant applications, Type A Charpy (Test Methods E 23) specimens and specimens suitable for testing in three point bending in accordance with Test Methods E 1921 or E 1820. Materials from irradiation programs (principally broken specimens) are reconstituted by welding end tabs of similar material onto remachined specimen sections that were unaffected by the initial test. Guidelines are given for the selection of suitable specimen halves and end tab materials, for dimensional control, and for avoidance of overheating the notch area. A comprehensive overview of the reconstitution methodologies can be found in Ref (1). 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard...

  17. Clean Cast Steel Technology: Effect of Micro-porosity on Tensile and Charpy Properties of Four Cast Steels

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, John, A.; Bates, Charles, E.

    2005-09-19

    The effect of these large shrink cavities on mechanical properties could be easily calculated using well established engineering formulas. Over the years, increases in computational and metallurgical resources have allowed the modeler to improve accuracy and increase the complexity of numerical predictors. An accurate prediction of micro-porosity, not observable using conventional radiographic techniques, and an engineering understanding of the effect on mechanical properties would give a designer confidence in using a more efficient casting design and a lower safety factor. This will give castings an additional design advantage. The goal of this project is to provide current and future modelers/designers with a tensile and Charpy property dataset for validation of micro-porosity predictors. The response of ultimate strength, elongation, and reduction in area to micro-porosity was very similar in all four alloys. Ultimate strength was largely unaffected by tensile fracture surface porosity until values of about 25% were reached and decreased linearly with increasing values. Elongation and reduction in area decreased sharply after less than 5% fracture surface porosity. Niyama values of about 0.7 were produced sound material and acceptable tensile properties. Ultrasonic velocities of 0.233 in/usec and higher produced acceptable tensile properties. Metallographic examination revealed a ratio of 4-6 to 1 in fracture surface porosity to metallographic porosity. Charpy impact properties were largely unaffected by the microporosity concentrations examined in this study and did not correlate to either Niyama values, fracture surface porosity, or metallographic porosity.

  18. Visual interface for the automation of the instrumented pendulum of Charpy tests used in the surveillance program of reactors vessel of nuclear power plants

    International Nuclear Information System (INIS)

    Inside the Programs of Surveillance of the nuclear power stations periodic information is required on the state that keep the materials with those that builds the vessel of the reactor. This information is obtained through some samples or test tubes that are introduced inside the core of the reactor and it is observed if its physical characteristics remain after having been subjected to the radiation changes and temperature. The rehearsal with the instrumented Charpy pendulum offers information on the behavior of fracture dynamics of a material. In the National Institute of Nuclear Research (ININ) it has an instrumented Charpy pendulum. The operation of this instrument is manual, having inconveniences to carry out rehearsals with radioactive material, handling of high and low temperatures, to fulfill the normative ones for the realization of the rehearsals, etc. In this work the development of a computational program is presented (virtual instrument), for the automation of the instrumented pendulum. The system has modules like: Card of data acquisition, signal processing, positioning system, tempered system, pneumatic system, compute programs like it is the visual interface for the operation of the instrumented Charpy pendulum and the acquisition of impact signals. This system shows that given the characteristics of the nuclear industry with radioactive environments, the virtual instrumentation and the automation of processes can contribute to diminish the risks to the personnel occupationally exposed. (Author)

  19. Investigation of Low Temperature Toughness and Crack Initiation In Welded Structural Steels

    OpenAIRE

    Vadholm, Therese

    2014-01-01

    A 420 MPa HSLA steel has been investigated. Instrumented Charpy impact tests and quasi-static CTOD tests have been performed on specimens of weld simulated Coarse Grained Heat Affected Zone (CGHAZ) and Intercritically Reheated Coarse Grained Heat Affected Zone (ICCGHAZ) microstructures. Charpy specimens with both a conventional V-notch and a sharp crack obtained by fatigue pre-cracking have been tested above and below the ductile-to-brittle transition temperature. The aim of the first two par...

  20. Irradiation programme MANITU: Results of pre-examinations and Charpy tests with unirradiated materials

    International Nuclear Information System (INIS)

    The irradiation project MANITU was planned in the frame of the European Long-term Fusion Materials Development Programme. The results of MANITU will have a lasting influence on the future actions within the materials development programme. The problem of the irradiation induced embrittlement of possible martensitic alloy candidates is still unsolved. But after the evaluation of sub-size Charpy tests with the unirradiated refrence specimens of MANITU a first tendency is recognizable. The Charpy properties of the newly developed low activation 7-10% Cr-WVTa alloys are clearly better compared with the modified commerical 10-11% Cr-NiMoVNb steels. In the present report the pre-examinations are documented and the Charpy test results with unirradiated reference specimens are analysed and assessed. (orig.)

  1. Evaluation of hydrogen embrittlement and temper embrittlement by key curve method in instrumented Charpy test

    Directory of Open Access Journals (Sweden)

    Makita A.

    2010-06-01

    Full Text Available Instrumented Charpy test was conducted on small sized specimen of 21/4Cr-1Mo steel. In the test the single specimen key curve method was applied to determine the value of fracture toughness for the initiation of crack extension with hydrogen free, KIC, and for hydrogen embrittlement cracking, KIH. Also the tearing modulus as a parameter for resistance to crack extension was determined. The role of these parameters was discussed at an upper shelf temperature and at a transition temperature. Then the key curve method combined with instrumented Charpy test was proven to be used to evaluate not only temper embrittlement but also hydrogen embrittlement.

  2. Visual interface for the automation of the instrumented pendulum of Charpy tests used in the surveillance program of reactors vessel of nuclear power plants; Interfase visual para la automatizacion del pendulo instrumentado de pruebas Charpy utilizado en el programa de vigilancia de la vasija de reactores de centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Rojas S, A.S.; Sainz M, E.; Ruiz E, J.A. [ININ, Carretera Mexico-Toluca Km.36.5, Mpio. de Ocoyoacac, Estado de Mexico (Mexico)]. E-mail: asrs@nuclear.inin.mx; esm@nuclear.inin.mx; jare@nuclear.inin.mx

    2004-07-01

    Inside the Programs of Surveillance of the nuclear power stations periodic information is required on the state that keep the materials with those that builds the vessel of the reactor. This information is obtained through some samples or test tubes that are introduced inside the core of the reactor and it is observed if its physical characteristics remain after having been subjected to the radiation changes and temperature. The rehearsal with the instrumented Charpy pendulum offers information on the behavior of fracture dynamics of a material. In the National Institute of Nuclear Research (ININ) it has an instrumented Charpy pendulum. The operation of this instrument is manual, having inconveniences to carry out rehearsals with radioactive material, handling of high and low temperatures, to fulfill the normative ones for the realization of the rehearsals, etc. In this work the development of a computational program is presented (virtual instrument), for the automation of the instrumented pendulum. The system has modules like: Card of data acquisition, signal processing, positioning system, tempered system, pneumatic system, compute programs like it is the visual interface for the operation of the instrumented Charpy pendulum and the acquisition of impact signals. This system shows that given the characteristics of the nuclear industry with radioactive environments, the virtual instrumentation and the automation of processes can contribute to diminish the risks to the personnel occupationally exposed. (Author)

  3. Laser weld reconstitution of conventional Charpy and Miniaturized Notch Test (MNT) specimens

    International Nuclear Information System (INIS)

    As nuclear power plants approach end-of-license (EOL) and consideration is given to license renewal, there is an ever increasing need to expand the amount of data obtainable from the original surveillance specimens. A laser welding technique to reconstitute broken Charpy specimens is being developed to produce both conventional and miniaturized Charpy specimens. This paper reports on early laser welding development efforts and summarizes previous proof-of-principle experiments on a 1/16 scale miniaturized Charpy test. In order to benchmark the laser welding procedure, the laser-reconstituted specimen data have been compared with the original specimen data. In addition, the microstructure after welding has been examined to ensure that the material in the vicinity of the notch is essentially unchanged after the welding process. Data which characterize the thermal transient during welding are obtained by attaching thermocouples to the specimens. Other important considerations include perturbation of the stress field near the notch, dynamic stress waves, and contact of the weld region with the tup. Precise control of welding parameters has been demonstrated, heat-affected zones as small as 0.25 mm can be achieved, and sufficient penetration depth can be obtained to enable welding thick sections (1T or greater) to yield conventional Charpy specimens or fracture toughness specimens and thin sections (∼5 mm) to yield Miniaturized Notch Test (MNT) specimens

  4. Dynamic fracture behavior of nodular cast iron

    International Nuclear Information System (INIS)

    Ferritic nodular cast iron has been found to be a much tougher material than previously believed based on Charpy impact test results. As a result this material is being considered as a substitute for Stainless Steel in nuclear waste transport containers. We have determined Klc and Kld values for nodular cast iron with varying values of silicon and percentage of pearlite in the matrix. Regular V-notch charpy bars and fatigue precracked charpy bars have been tested to determine the initiation and propagation energy and the effect of notch acuity on transition temperature. (author)

  5. Identification of neutron irradiation induced strain rate sensitivity change using inverse FEM analysis of Charpy test

    International Nuclear Information System (INIS)

    A simple methodology how to obtain additional information about the mechanical behaviour of neutron-irradiated WWER 440 reactor pressure vessel steel was developed. Using inverse identification, the instrumented Charpy test data records were compared with the finite element computations in order to estimate the strain rate sensitivity of 15Ch2MFA steel irradiated with different neutron fluences. The results are interpreted in terms of activation volume change

  6. Low temperature impact testing of welded structural wrought iron

    Science.gov (United States)

    Rogers, Zachary

    During the second half of the 19th century, structural wrought iron was commonly used in construction of bridges and other structures. Today, these remaining structures are still actively in use and may fall under the protection of historic preservation agencies. Continued use and protection leads to the need for inspection, maintenance, and repair of the wrought iron within these structures. Welding can be useful to achieve the appropriate repair, rehabilitation, or replacement of wrought iron members. There is currently very little published on modern welding techniques for historic wrought iron. There is also no pre-qualified method for this welding. The demand for welding in the repair of historic structural wrought iron has led to a line of research investigating shielded metal arc welding (SMAW) of historic wrought iron at the University of Colorado Denver. This prior research selected the weld type and other weld specifications to try and achieve a recognized specific welding procedure using modern SMAW technology and techniques. This thesis continues investigating SMAW of historic wrought iron. Specifically, this thesis addresses the toughness of these welds from analysis of the data collected from performing Charpy V-Notch (CVN) Impact Tests. Temperature was varied to observe the material response of the welds at low temperature. The wrought iron used in testing was from a historic vehicle bridge in Minnesota, USA. This area, and many other areas with wrought iron structures, can experience sustained or fluctuating temperatures far below freezing. Investigating the toughness of welds in historic wrought iron at these temperatures is necessary to fully understand material responses of the existing structures in need of maintenance and repair. It was shown that welded wrought iron is tougher and more ductile than non-welded wrought iron. In regards to toughness, welding is an acceptable repair method. Information on wrought iron, low temperature failure

  7. Residual stress study by neutron diffraction in the Charpy specimens reconstructed by various welding methods

    International Nuclear Information System (INIS)

    The investigation of welding residual stress is very important for nuclear industry since it can considerably affect the structural integrity of various components and products and their lifetime. In order to evaluate the applicability of various welding methods the residual stress in test Charpy specimens welded by various techniques were analysed using high resolution neutron diffraction. The experiments show that the level of residual stress in welds can be quite high and this fact should be considered when choosing an appropriate welding technique. Key words: neutron diffraction, residual stress, welding

  8. Crack lengths calculation by the unloading compliance technique for Charpy size specimens

    International Nuclear Information System (INIS)

    The problems with the crack length determination by the unloading compliance method are well known for Charpy size specimens. The final crack lengths calculated for bent specimens do not fulfil ASTM 1820 accuracy requirements. Therefore some investigations have been performed to resolve this problem. In those studies it was considered that the measured compliance should be corrected for various factors, but satisfying results were not obtained. In the presented work the problem was attacked from the other side, the measured specimen compliance was taken as a correct value and what had to be adjusted was the calculation procedure. On the basis of experimentally obtained compliances of bent specimens and optically measured crack lengths the investigation was carried out. Finally, a calculation procedure enabling accurate crack length calculation up to 5 mm of plastic deflection was developed. Applying the new procedure, out of investigated 238 measured crack lengths, more than 80% of the values fulfilled the ASTM 1820 accuracy requirements, while presently used procedure provided only about 30% of valid results. The newly proposed procedure can be also prospectively used in modified form for specimens of a size different than Charpy size. (orig.)

  9. Influence of Loading Rate on the Calibration of Instrumented Charpy Strikers

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; Scibetta, M.; McColskey, D.; McCowan, C.

    2009-01-15

    One of the key factors for obtaining reliable instrumented Charpy results is the calibration of the instrumented striker. The conventional approach for establishing an analytical relationship between strain gage output and force applied to the transducer is the static calibration, which is preferably performed with the striker installed in the pendulum assembly. However, the response of an instrumented striker under static force application may sometimes differ significantly from its dynamic performance during an actual Charpy test. This is typically reflected in a large difference between absorbed energy returned by the pendulum encoder (KV) and calculated under the instrumented force/displacement test record (Wt). Such difference can be either minimized by optimizing the striker design or analytically removed by adjusting forces and displacements until KV = Wt (the so-called 'Dynamic Force Adjustment'). This study investigates the influence of increasing force application rates on the force/voltage characteristics of two instrumented strikers, one at NIST in Boulder, CO and one at SCK-CEN in Mol, Belgium.

  10. Enhancements in Magnesium Die Casting Impact Properties

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Yulong Zhu; Srinath Viswanathan; Shafik Iskander

    2000-06-30

    The need to produce lighter components in transportation equipment is the main driver in the increasing demand for magnesium castings. In many automotive applications, components can be made of magnesium or aluminum. While being lighter, often times the magnesium parts have lower impact and fatigue properties than the aluminum. The main objective of this study was to identify potential improvements in the impact resistance of magnesium alloys. The most common magnesium alloys in automotive applications are AZ91D, AM50 and AM60. Accordingly, these alloys were selected as the main candidates for the study. Experimental quantities of these alloys were melted in an electrical furnace under a protective atmosphere comprising sulfur hexafluoride, carbon dioxide and dry air. The alloys were cast both in a permanent mold and in a UBE 315 Ton squeeze caster. Extensive evaluation of tensile, impact and fatigue properties was conducted at CWRU on permanent mold and squeeze cast test bars of AZ91, AM60 and AM50. Ultimate tensile strength values between 20ksi and 30ksi were obtained. The respective elongations varied between 25 and 115. the Charpy V-notch impact strength varied between 1.6 ft-lb and 5 ft-lb depending on the alloy and processing conditions. Preliminary bending fatigue evaluation indicates a fatigue limit of 11-12 ksi for AM50 and AM60. This is about 0.4 of the UTS, typical for these alloys. The microstructures of the cast specimens were investigated with optical and scanning electron microscopy. Concomitantly, a study of the fracture toughness in AM60 was conducted at ORNL as part of the study. The results are in line with values published in the literature and are representative of current state of the art in casting magnesium alloys. The experimental results confirm the strong relationship between aluminum content of the alloys and the mechanical properties, in particular the impact strength and the elongation. As the aluminum content increases from about 5

  11. Characterization by notched and precracked Charpy tests of the in-service degradation of RPV steel fracture toughness

    Energy Technology Data Exchange (ETDEWEB)

    Fabry, A.

    1997-01-01

    The current engineering and regulatory practice to estimate fracture toughness safety margins for nuclear reactor pressure vessels (RPVs) relies heavily on the CVN impact test. Techniques to estimate in-service toughness degradation directly using a variety of precracked specimens are under development worldwide. Emphasis is on their miniaturization. In the nuclear context, it is essential to address many issues such as representativity of the surveillance programs with respect to the vessel in terms of materials and environment, transferability of test results to the structure (constraint and size effects), lower bound toughness certification, creadibility relative to trends of exising databases. An enhanced RPV surveillance strategy in under development in Belgium. It combines state-of-the-art micromechanical and damage modelling to the evaluation of CVN load-deflection signals, tensile stress-strain curves and slow-bend tests of reconstituted precracked Charpy specimens. A probabilistic micromechanical model has been established for static and dynamic transgranular cleavage initiation fracture toughness in the ductile-brittle transition temperature range. This model allows to project toughness bounds for any steel embrittlement condition from the corresponding CVN and static tensile properties, using a single scaling factor defined by imposing agreement with toughness tests in a single condition. The outstanding finding incorporated by this toughness transfer model is that the microcleavage fracture stress is affected by temperature in the ductile-brittle transition and that this influence is strongly correlated to the flow stress: this explains the shape of the K{sub Ic}n K{sub Id} temperature curves as well as the actual magnitude of the strain rate and irradiation effects. Furthermore, CVN crack arrest loads and fracture appearance are also taken advantage of in order to estimate K{sub Ia} degradation. Finally, the CVN-tensile load-temperature diagram

  12. Charpy notch toughness and hardness of reheated martensite and lower bainite

    Directory of Open Access Journals (Sweden)

    F. Vodopivec

    2010-07-01

    Full Text Available A high strength low alloyed (HSLA V-Nb steel was heat treated to martensite and lower bainite with different grain size, reheated for 3 seconds at 750 °C and air cooled. Charpy notch tests were performed from -100 °C to 60 °C and the hardness assessed at room temperature. For as delivered steel and lower bainite, the upper shelf toughness was above 200 J and the transition temperature low, while, for martensite the upper shelf toughness threshold was aproximateky at 0 °C. After reheating, notch toughness was decreased moderatly for martensite and strongly for lower bainite. Independently on grain size, lower bainite was more propensive than martensite to embritlement after short reheating in the (α + β range. For martensite, the change of notch toughness was not related to change of hardness, as by lower hardness lower, also toughness was lower.

  13. On the Use of the Master Curve based on the Precracked Charpy Specimen

    International Nuclear Information System (INIS)

    Recently, worldwide interest has been demonstrated in the evaluation of the use of the Master Curve approach to characterize fracture toughness of ferritic steels in the transition regime. This was acknowledged by the recent release of the ASTM Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range (E1921). The present work aims to investigate the use of the Charpy specimen along with the Master Curve approach to derive the fracture toughness behaviour of reactor pressure vessel steels. Therefore, four well characterized and documented reactor pressure vessel steels were selected. A large experimental program to measure fracture toughness with Charpy size specimens was carried out. Four important aspects were investigated: (1) the T0 determination as a function of test temperature; (2) the E1921 specimen size requirement (factor M=30); (3) the censoring procedure for specimens not satisfying the E1921 size requirements; (4) the estimation of the fracture toughness lower bound, and its comparison to the ASME KIC curve. It is found that within the experimental and statistical uncertainties, the reference temperature T0 is not affected by the test temperature, even when data are not valid according to E1921 requirements. By application of the censoring procedure, the determination of the reference temperature may lead to non conservative results. Comparison to larger specimen size suggests the use of M=60 rather than 30 to limit the loss of constraint, in agreement with finite element calculations. Nevertheless, the differences are not large enough to be statistically significant. The lower bound based on the Master Curve is very close to the experimental lower bound, while the ASME KIC curve trends to be over conservative. Replacing RTNDT by the new index, RTTo, in the ASME KIC equation reduces this over conservatism

  14. On the Use of the Master Curve based on the Precracked Charpy Specimen

    Energy Technology Data Exchange (ETDEWEB)

    Chaouadi, R.; Scibetta, M.; Van Walle, E.; Gerard, R

    1999-08-01

    Recently, worldwide interest has been demonstrated in the evaluation of the use of the Master Curve approach to characterize fracture toughness of ferritic steels in the transition regime. This was acknowledged by the recent release of the ASTM Standard Test Method for Determination of Reference Temperature, T{sub 0}, for Ferritic Steels in the Transition Range (E1921). The present work aims to investigate the use of the Charpy specimen along with the Master Curve approach to derive the fracture toughness behaviour of reactor pressure vessel steels. Therefore, four well characterized and documented reactor pressure vessel steels were selected. A large experimental program to measure fracture toughness with Charpy size specimens was carried out. Four important aspects were investigated: (1) the T0 determination as a function of test temperature; (2) the E1921 specimen size requirement (factor M=30); (3) the censoring procedure for specimens not satisfying the E1921 size requirements; (4) the estimation of the fracture toughness lower bound, and its comparison to the ASME KIC curve. It is found that within the experimental and statistical uncertainties, the reference temperature T0 is not affected by the test temperature, even when data are not valid according to E1921 requirements. By application of the censoring procedure, the determination of the reference temperature may lead to non conservative results. Comparison to larger specimen size suggests the use of M=60 rather than 30 to limit the loss of constraint, in agreement with finite element calculations. Nevertheless, the differences are not large enough to be statistically significant. The lower bound based on the Master Curve is very close to the experimental lower bound, while the ASME K{sub IC} curve trends to be over conservative. Replacing RT{sub NDT} by the new index, RT{sub To}, in the ASME KIC equation reduces this over conservatism.

  15. Comparison between instrumented precracked Charpy and compact specimen tests of carbon steels

    International Nuclear Information System (INIS)

    The General Atomic Company High Temperature Gas-Cooled Reactor (HTGR) is housed within a prestressed concrete reactor vessel (PCRV). Various carbon steel structural members serve as closures at penetrations in the vessel. A program of testing and evaluation is underway to determine the need for reference fracture toughness (K/sub IR/) and indexing procedures for these materials as described in Appendix G to Section III, ASME Code for light water reactor steels. The materials of interest are carbon steel forgings (SA508, Class 1) and plates (SA537, Classes 1 and 2) as well as weldments of these steels. The fracture toughness behavior is characterized with instrumented precracked Charpy V-votch specimens (PCVN) - slow-bend and dynamic - and compact specimens (10-mm and 25-mm thicknesses) using both linear elastic (ASTM E399) and elastic-plastic (equivalent Energy and J-Integral) analytical procedures. For the dynamic PCVN tests, force-time traces are analyzed according to the procedures of the Pressure Vessel Research Council (PVRC)/Metal Properties Council (MPC). Testing and analytical procedures are discussed and PCVN results are compared to those obtained with compact specimens

  16. Applicability of smaller than Charpy specimens for fracture toughness characterization with the VTT method

    International Nuclear Information System (INIS)

    The term fracture toughness usually refers to the linear elastic fracture resistance parameter KIC. In the case of structural steels, the estimation of KIC is limited to the lower shelf of toughness or require extremely large specimens. This specimen size requirement has been one major obstacle for applying fracture mechanics in structural integrity assessment outside aviation, nuclear and off-shore industries. During the last decade, a statistical data treatment methodology, based on a micro-mechanistic cleavage fracture model, combined with elastic plastic finite element analysis has enabled the fracture toughness to be characterized with small specimens in the ductile-to-brittle transition region. The methodology is known as the VTT method or the Master Curve procedure. The development has led to a new testing standard for fracture toughness testing of ferritic steels in the transition range. Here, the premises for the methodology are described and its validity range is discussed. Presently the methodology has been validated for as small as 10.10 mm2 bend specimens, but the use of even smaller specimens is under investigation. Specifically, results obtained with three different sub-Charpy specimen configurations are presented and discussed. (author)

  17. Re-utilization by '' Stud Welding'' of capsules charpy-V belonged to surveillance programs

    International Nuclear Information System (INIS)

    The perspectives of nuclear plants life extension that are approximating to their end of design life compels to make new surveillance programs. The re-utilization of specimens belonging to surveillance capsules already tested in these new surveillance programs seems be a solution worldwide accepted. The two possible re-utilization processes of this irradiated material are: Subsized specimens and Reconstitution. While the first alternative (Subsized specimens) outlines serious problems for apply the results, the reconstitution eliminates this problem, since the resulting specimens after of the reconstruction procedure would be of the same dimensions that the original. The reconstruction process involves welds, and therefore it has associated the specific problems of this type of joints. Furthermore, by be tried to material irradiated with certain degree of internal damage, that is the variable to evaluate, requires that the heat contribution to the piece not originate local thermal treatments that alter its mechanical qualities. In this work has been followed the evolution by the variables of the weld process and their influence on the quality by the union from metallographic al point of view as well as mechanical for a weld procedure by Stud Welding. The principal objective is to optimize said parameters to assure a good mechanical continuity, without detriment of the microstructural characteristics of the original material. To verify this last have been accomplished with metallographical tests, temperature profile, hardness and will be carried out also Charpy tests. (Author)

  18. On the measurement of fatigue crack growth rates of steels using non-standard specimens

    International Nuclear Information System (INIS)

    Fatigue crack growth rates were measured using K-Decreasing Method during precracking of standard (Compact Tension) and non-standard (Charpy V -notch and Three-Point-Bend) specimens of four ferritic steels. Crack growth rates from the specimens were then inter-compared. The results from Compact Tension specimens were within ±15% error bar of the results from Three-Point-Bend specimens and were within ±6% error bar of the results from Charpy V -notch. The inter-comparison of the mean crack growth rates of any of the steels as obtained using different specimen geometries did not reveal any systematic dependence of crack growth rates vis-a-vis the specimens utilized. The experimental results suggested the possibility of generating material crack growth rate data as a bonus during fatigue precracking of fracture toughness specimens including Charpy V-notch and Three-Point-Bend specimens. The results also indicated distinct possibility of the measurement of steady state fatigue crack growth rate of irradiated steels using either Compact Tension and Three-Point-Bend fracture toughness specimens with a/W ≤ 0.65 or during precrackingstep of a few designated impact specimens from surveillance locations to be used as fracture toughness specimens for generation of irradiated material fracture toughness data. (author)

  19. Transverse and z-Direction CVN Impact Tests of X65 Line Pipe Steels of Two Centerline Segregation Ratings

    Science.gov (United States)

    Su, Lihong; Li, Huijun; Lu, Cheng; Li, Jintao; Fletcher, Leigh; Simpson, Ian; Barbaro, Frank; Zheng, Lei; Bai, Mingzhuo; Shen, Jianlan; Qu, Xianyong

    2016-08-01

    Centerline segregation occurs as a positive concentration of alloying elements in the mid-thickness region of continuously cast slab. Depending upon its severity, it may affect mechanical properties and potentially downstream processing such as weldability, particularly for high-strength line pipe. The segregation fraction in continuously cast slabs and corresponding hot-rolled strips was assessed on API 5L grade X65 line pipe steels with different levels of segregation, rated as Mannesmann 2.0 and 1.4. The results showed that the segregation fraction in hot-rolled strip samples was in accordance with that assessed in the cast slabs, and the segregated regions in hot-rolled strip samples were found to be discontinuous. Transverse and z-direction CVN impact tests were conducted on the two strips and the results showed that centerline segregation does have an influence on the Charpy impact properties of line pipe steel. Specimens located at segregated regions exhibited lower Charpy impact toughness and strips rolled from slabs with higher segregation levels are more likely to exhibit greater variability in Charpy impact toughness. The influence of centerline segregation on z-direction Charpy impact toughness is more severe than on transverse Charpy impact toughness. Lower Charpy impact toughness and brittle fracture surface with cleavage facets along with rod-shaped MnS inclusions were observed for the strip rolled from slab with 2.0 segregation rating if the Charpy specimens were located at segregated regions. The influence on Charpy impact toughness can be associated with the pearlite structure at the centerline and level of MnS inclusions.

  20. Transverse and z-Direction CVN Impact Tests of X65 Line Pipe Steels of Two Centerline Segregation Ratings

    Science.gov (United States)

    Su, Lihong; Li, Huijun; Lu, Cheng; Li, Jintao; Fletcher, Leigh; Simpson, Ian; Barbaro, Frank; Zheng, Lei; Bai, Mingzhuo; Shen, Jianlan; Qu, Xianyong

    2016-06-01

    Centerline segregation occurs as a positive concentration of alloying elements in the mid-thickness region of continuously cast slab. Depending upon its severity, it may affect mechanical properties and potentially downstream processing such as weldability, particularly for high-strength line pipe. The segregation fraction in continuously cast slabs and corresponding hot-rolled strips was assessed on API 5L grade X65 line pipe steels with different levels of segregation, rated as Mannesmann 2.0 and 1.4. The results showed that the segregation fraction in hot-rolled strip samples was in accordance with that assessed in the cast slabs, and the segregated regions in hot-rolled strip samples were found to be discontinuous. Transverse and z-direction CVN impact tests were conducted on the two strips and the results showed that centerline segregation does have an influence on the Charpy impact properties of line pipe steel. Specimens located at segregated regions exhibited lower Charpy impact toughness and strips rolled from slabs with higher segregation levels are more likely to exhibit greater variability in Charpy impact toughness. The influence of centerline segregation on z-direction Charpy impact toughness is more severe than on transverse Charpy impact toughness. Lower Charpy impact toughness and brittle fracture surface with cleavage facets along with rod-shaped MnS inclusions were observed for the strip rolled from slab with 2.0 segregation rating if the Charpy specimens were located at segregated regions. The influence on Charpy impact toughness can be associated with the pearlite structure at the centerline and level of MnS inclusions.

  1. Statistical Analysis of Charpy Transition Temperature Shift in Reactor Pressure Vessel Steels: Application of Nuclear Materials Database(MatDB)

    International Nuclear Information System (INIS)

    The MDPortal contains various technical documents on the degradation and development of nuclear materials. Additionally, the nuclear materials database (MatDB) is also launched in KAERI recently. The MatDB covers the mechanical properties of various nuclear structural materials used as the components: a reactor pressure vessel, steam generator, and primary and secondary piping. In this study, we introduced MatDB briefly, and analyzed the Charpy transition temperature shift in reactor pressure vessel steels of Korean nuclear power plants retrieved from MatDB. It can show an application of the MatDB to the real case of material degradations in NPPs. The MatDB includes the tensile results, Charpy results, fatigue results and J-R curve results at present. In the future other properties such as creep, fracture toughness, and SCC degradations are going to be added consistently. The data from MatDB were successfully applied to estimate the TTS analysis of Korean RPV steels in surveillance tests

  2. Impact toughness of tungsten films deposited on martensite stainless steel

    Institute of Scientific and Technical Information of China (English)

    HUANG Ning-kang; YANG Bin; WANG De-zhi

    2005-01-01

    Tungsten films were deposited on stainless steel Charpy specimens by magnetron sputtering followed by electron beam heat treatment. Charpy impact tests and scanning electron microscopy were used to investigate the ductile-brittle transition behavior of the specimens. With decreasing test temperature the fracture mode was transformed from ductile to brittle for both kinds of specimens with and without W films. The data of the crack initiation energy, crack propagation energy, impact absorbing energy, fracture time and deflection as well as the fracture morphologies at test temperature of -70 ℃ show that W films can improve the impact toughness of stainless steel.

  3. 碰撞试验

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Drop impact test - mechanics & physics of failure; Drop-impact simulation and experimental verification for spindle fixation of video and audio module;Ductile-brittle transition evaluation of Japanese sword and weld metals using miniaturized impact specimens;Dynamic behavior of high polymers with focus on a macrolon;Dynamic J{sub}R curves of 308 stainless steel weld from instrumented impact test of unprecracked Charpy V-notch specimens;Dynamic mechanical analysis and toughening mechanisms of polycarbonate and 4,4'-dihydorxydiphenyl copolycarbonate;……

  4. Influence of Martensite Volume Fraction on Impact Properties of Triple Phase (TP) Steels

    Science.gov (United States)

    Zare, Ahmad; Ekrami, A.

    2013-03-01

    Ferrite-bainite-martensite triple phase (TP) microstructures with different volume fractions of martensite were obtained by changing heat treatment time during austempering at 300 °C. Room temperature impact properties of TP steels with different martensite volume fractions ( V M) were determined by means of Charpy impact testing. The effects of test temperature on impact properties were also investigated for two selected microstructures containing 0 (the DP steel) and 8.5 vol.% martensite. Test results showed reduction in toughness with increasing V M in TP steels. Fracture toughness values for the DP and TP steels with 8.5 vol.% martensite were obtained from correlation between fracture toughness and the Charpy impact energy. Fractography of Charpy specimens confirmed decrease in TP steels' toughness with increasing V M by considering and comparing radial marks and crack initiation regions at the fracture surfaces of the studied steels.

  5. 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.

  6. Proceedings of a C.S.N.I. specialist meeting on instrumented pre-cracked Charpy testing

    International Nuclear Information System (INIS)

    This report presents the status of the testing and data analysis procedures for the instrumented pre-cracked Charpy test with emphasis on the application of the test technique to the nuclear industry. The report (Proceedings) consist of invited technical papers by specialists in the field and a synopsis of the comments, conclusions, and recommendations reached in a workshop session. The CSNl-sponsored and EPRI-hosted meeting confirmed both the popularity of the test technique in the nuclear industry and the problems associated with the test technique due to the lack of a national or international consensus standard. Major emphasis in the meeting was devoted to evaluating the existing industry testing procedure (EPRI procedure) and proposed national standards (ASTM, ASK). The EPRI procedures were considered adequate by specialists concerned with engineering applications, but too restrictive by specialists concerned with research applications. As a result of the conference, a compilation of state-of-the-art papers is now available to code and standard committees. Specific comments concerning test and data analysis procedures, applications in the nuclear industry, and future research areas are also contained in the proceedings

  7. Prediction of quenched and tempered steel and cast steel properties

    Directory of Open Access Journals (Sweden)

    B. Smoljan

    2011-12-01

    Full Text Available Purpose: The influence of processing parameters, such as pouring temperature and cooling rate during the casting, as well as application of hot working and pre-heat treatment, on strength and toughness of quenched and tempered steel was investigated.Design/methodology/approach: Strength and toughness were presented by yield strength and Charpy-V notch toughness, respectively. Experimental procedure of material properties optimization was done using the 25-2 factor experiment.Findings: It was found out that yield strength is insensitive on differences between applied manufacturing processes, but by application of hot working and with appropriate pouring temperature the Charpy-V notch toughness is increased. Also, Charpy-V notch toughness is increased by interactive effect of the appropriate cooling rate during the casting and application of hot working.Research limitations/implications: The research was focused mainly on Charpy-V notch toughness of carbon and low alloyed heat treatable steels.Practical implications: The established algorithms can be used for prediction of tensile strength, yield strength and Charpy-V notch toughness in heat treating practice.Originality/value: Original relation for prediction of quenched and tempered steel and cast steel Charpy-V notch toughness are developed.

  8. 真空热处理

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    [篇名 ] Relations between fracture toughness, hardness and microstructure of vacuum heat-treated high-speed steel,[ 篇名 ] Flexible furnace concepts for vacuum heat treatment using high-pressure gas quenching,[ 篇名 ] Effect of boron micro-alloying on microstructure and mechanical properties of fine-grained CM247LC superalloy,[ 篇名] PROPERTIES OF POLYCRYSTALS SINTERED AT HIGH PRESSURES FROM DIAMOND NANOPOWDERS PRODUCED BY DETONATION AND STATIC SYNTHESES,[ 篇名 ] The Effects of Steel Quality, Vacuum Heat Treatment Quench Rate and Charpy V-Notch Impact Test Temperature on the Impact Toughness and Microstructure of Premium Quality H-13 Tool Steel。

  9. Fracture Toughness Evaluation of Kori-1 RPV Beltline Weld for a Long-Term Operation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bong-Sang; Kim, Min-Chul; Ahn, Sang-Bok; Kim, Byung-Chul; Hong, Jun-Hwa [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2007-07-01

    Irradiation embrittlement of RPV (reactor pressure vessel) material is the most important aging issue for a long-term operation of nuclear power plants. KORI unit 1, which is the first PWR in Korea, is approaching its initial licensing life of 30 years. In order to operate the reactor for another 10 years and more, it should be demonstrated that the irradiation embrittlement of the reactor will be adequately managed by ensuring that the fracture toughness properties have a certain level of the safety margin. The current regulation requires Charpy V-notch impact data through conventional surveillance tests. It is based on the assumption that Charpy impact test results are well correlated with the fracture toughness properties of many engineering steels. However, Charpy V-notch impact data may not be adequate to estimate the fracture toughness of certain materials, such as Linde 80 welds. During the last decade, a tremendous number of fracture toughness data on many RPV steels have been produced in accordance with the new standard test method, the so-called master curve method. ASTM E1921 represents a revolutionary advance in characterizing fracture toughness of RPV steels, since it permits establishing the ductile to brittle transition portion of the fracture toughness curve with direct measurements on a relatively small number of relatively small specimens, such as pre-cracked Charpy specimens. Actual fracture toughness data from many different RPV steels revealed that the Charpy test estimations are generally conservative with the exception of a few cases. Recent regulation codes in USA permit the master curve fracture toughness methodology in evaluating an irradiation embrittlement of commercial nuclear reactor vessels.

  10. 46 CFR 54.05-20 - Impact test properties for service of 0 °F and below.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Impact test properties for service of 0 °F and below... ENGINEERING PRESSURE VESSELS Toughness Tests § 54.05-20 Impact test properties for service of 0 °F and below. (a) Test energy. The impact energies of each set of transverse Charpy specimens may not be less...

  11. Impact energy analysis of HSLA specimens after simulated welding thermal cycle

    Directory of Open Access Journals (Sweden)

    Samarždić, I.

    2008-04-01

    Full Text Available This paper presents impact energy results of specimens made from high strength fine grained steel TStE 420 after thermal cycle simulation. These results are obtained by examining Charpy specimens. Metallographic analysis is performed, hardness is measured and total impact energy is divided into ductile and brittle components.

  12. Impact energy analysis of HSLA specimens after simulated welding thermal cycle

    OpenAIRE

    Samarždić, I.; Aračić, S.; Duđner, M.

    2008-01-01

    This paper presents impact energy results of specimens made from high strength fine grained steel TStE 420 after thermal cycle simulation. These results are obtained by examining Charpy specimens. Metallographic analysis is performed, hardness is measured and total impact energy is divided into ductile and brittle components.

  13. Effect of copper content on the microstructure and mechanical properties of multipass MMA, low alloy steel weld metal deposits

    International Nuclear Information System (INIS)

    Effect of copper content in the range of 0.14-0.94 wt.% on the microstructure and mechanical properties of Cr-Ni-Cu low alloy steel weld metal deposits was investigated. All welds were prepared by manual metal arc welding technique in flat position. Microstructure of the welds was examined by optical and scanning electron microscopes. The results showed increase in acicular ferrite and microphases formed at the expense of primary ferrite and ferrite with second phase with steady refinement of microstructure. According to these microstructural changes, hardness, yield and ultimate tensile stresses increased while Charpy V-notch impact toughness and percent elongation reduced.

  14. Definition of the minimum longitude of insert in the rebuilding of Charpy test tubes for surveillance and life extension of vessels in Mexico

    International Nuclear Information System (INIS)

    In the National Institute of Nuclear Research (Mexico) a welding system for the rebuilding of Charpy test tubes has been developed, automated, qualified and used for the surveillance of the mechanical properties (mainly embrittlement) of the vessel. This system uses the halves of the rehearsed Charpy test tubes of the surveillance capsules extracted of the reactors, to obtain, of a rehearsed test tube, two reconstituted test tubes. This rebuilding process is used so much in the surveillance program like in the potential extension of the operation license of the vessel. To the halves of Charpy test tubes that have been removed the deformed part by machine are called -insert- and in a very general way the rebuilding consists in weld with the welding process -Stud Welding- two metallic implants in the ends of the insert, to obtain a reconstituted test tube. The main characteristic of this welding are the achieved small dimensions, so much of the areas welded as of the areas affected by the heat. The applicable normative settles down that the minim longitude of the insert for the welding process by Stud Welding it should be of 18 mm, however according to the same normative this longitude can diminish if is demonstrated analytic or experimentally that the central volume of 1 cm3 in the insert is not affected. In this work the measurement of the temperature profiles to different distances of the welding interface is presented, defining an equation for the maximum temperatures reached in function of the distance, on the other hand the real longitude affected in the test tube by means of metallography is determined and this way the minimum longitude of the insert for this developed rebuilding system was determined. (Author)

  15. Impact energy analysis of quenched and tempered fine grain structural steel specimens after weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2014-10-01

    Full Text Available The paper presents impact energy results of thermal cycle simulated specimens of quenched and tempered fine grain structural steel S960QL. These results are obtained by examining notched Charpy specimens. Upon performed metallographic analysis and measured hardness, total impact energy is separated into ductile and brittle components.

  16. Evaluation of impact and fatigue properties on austempered ductile iron

    OpenAIRE

    Arias Fernández, Sergio

    2009-01-01

    Austempered Ductile Iron (ADI) proved to be an excellent material as it possesses attractive properties: high strength, ductility and toughness are combined with good wear resistance and machinability. In this work impact and the fatigue properties have been evaluated for low alloyed Austempered Ductile Iron. To do this, Charpy-type impact test for austempered ductile iron was performed by the standard ASTM A 327M and Fatigue Crack Growth Rates (FCGR) were measured by the stand...

  17. Definition of the minimum longitude of insert in the rebuilding of Charpy test tubes for surveillance and life extension of vessels in Mexico; Definicion de la longitud minima de inserto en la reconstitucion de probetas Charpy para vigilancia y extension de vida de vasijas en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Romero C, J.; Hernandez C, R.; Rocamontes A, M., E-mail: jesus.romero@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-11-15

    In the National Institute of Nuclear Research (Mexico) a welding system for the rebuilding of Charpy test tubes has been developed, automated, qualified and used for the surveillance of the mechanical properties (mainly embrittlement) of the vessel. This system uses the halves of the rehearsed Charpy test tubes of the surveillance capsules extracted of the reactors, to obtain, of a rehearsed test tube, two reconstituted test tubes. This rebuilding process is used so much in the surveillance program like in the potential extension of the operation license of the vessel. To the halves of Charpy test tubes that have been removed the deformed part by machine are called -insert- and in a very general way the rebuilding consists in weld with the welding process -Stud Welding- two metallic implants in the ends of the insert, to obtain a reconstituted test tube. The main characteristic of this welding are the achieved small dimensions, so much of the areas welded as of the areas affected by the heat. The applicable normative settles down that the minim longitude of the insert for the welding process by Stud Welding it should be of 18 mm, however according to the same normative this longitude can diminish if is demonstrated analytic or experimentally that the central volume of 1 cm{sup 3} in the insert is not affected. In this work the measurement of the temperature profiles to different distances of the welding interface is presented, defining an equation for the maximum temperatures reached in function of the distance, on the other hand the real longitude affected in the test tube by means of metallography is determined and this way the minimum longitude of the insert for this developed rebuilding system was determined. (Author)

  18. A Metallurgical Evaluation of the Powder-Bed Laser Additive Manufactured 4140 Steel Material

    Science.gov (United States)

    Wang, Wesley; Kelly, Shawn

    2016-03-01

    Using laser powder bed fusion (PBF-L) additive manufacturing (AM) process for steel or iron powder has been attempted for decades. This work used a medium carbon steel (AISI 4140) powder to explore the feasibility of AM. The high carbon equivalent of 4140 steel (CEIIW ≈ 0.83) has a strong tendency toward cold cracking. As such, the process parameters must be carefully controlled to ensure the AM build quality. Through an orthogonally designed experimental matrix, a laser-welding procedure was successfully developed to produce 4140 steel AM builds with no welding defects. In addition, the microstructure and micro-cleanliness of the as-welded PBF-L AM builds were also examined. The results showed an ultra-fine martensite lath structure and an ultra-clean internal quality with minimal oxide inclusion distribution. After optimizing the PBF-L AM process parameters, including the laser power and scan speed, the as-welded AM builds yielded an average tensile strength higher than 1482 MPa and an average 33 J Charpy V-notch impact toughness at -18°C. The surface quality, tensile strength, and Charpy V-notch impact toughness of AM builds were comparable to the wrought 4140 steel. The excellent mechanical properties of 4140 steel builds created by the PBF-L AM AM process make industrial production more feasible, which shows great potential for application in the aerospace, automobile, and machinery industries.

  19. Test Technique Development on the Irradiated Reconstituted PCVN Specimen in Hot Cell

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sangbok; Oh, Wanho; Choo, Yongsun; Kim, Minchul; Lee, Bongsang [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2006-07-01

    The degradation of fracture toughness is the important factor to restrict the life of nuclear pressure vessel in PWR reactors. A pressure vessel is operated in conformity with the fracture analysis based on ASME codes to ensure safety margins from the unstable fracture. A fracture analysis is performed based on the result from the Charpy impact tests in PWR reactor, but it has the questions to be exact solutions because the test results give indirect and excessively conservative values. Therefore the research to find an exact toughness parameter is undergoing to use the pre-cracked Charpy v-notch (PCVN). As results the master curve method is proposed in ASTM E1921 to be supposed an appropriate tool to evaluate the fracture toughness for the irradiated, or the operated pressure vessel materials. The surveillance test program to evaluate toughness degradation on existing commercial PWR reactor is performed through the impact test on Charpy specimens. It gives the lack of the specimen to evaluate the safety in toughness for on-going operation beyond design life. To overcome the shortage of specimen, the test method to use a reconstituted PCVN specimen fabricated from the broken half of Charpy specimen is proposed and adopted in foreign reactors. In this paper techniques developed for the reconstituted specimen from the domestic commercial PWR reactor in hot cell are described.

  20. Investigations on the impact strength of constructional high-strength Weldox steel at lowered temperature

    OpenAIRE

    W. Ozgowicz; E. Kalinowska-Ozgowicz

    2008-01-01

    Purpose: The paper presents the results of investigations concerning the impact strength of thick steel plates at lowered temperature obtained by industrial smelting of micro-alloyed steel of the type S1100QL (Weldox 1100) and S1300QL (Weldox 1300) with a yield strength of 1100-1300 MPa.Design/methodology/approach: The main methods used for these researches were the impact test Charpy V at lower temperatures, and metallographic observations. The tested samples at lower temperature have also b...

  1. Effect of phosphorous and boron addition on microstructural evolution and Charpy impact properties of high-phosphorous-containing plain carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seokmin [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Shin, Sang Yong [Microstructure Physics and Alloy Design, Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf D-40237 (Germany); Lee, Junghoon [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, Chang-Hoon [Next Generation Products Research Group, Technical Research Laboratories, POSCO, Pohang 790-785 (Korea, Republic of); Lee, Sunghak, E-mail: shlee@postech.ac.kr [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2013-03-01

    Four plain carbon steels were fabricated by controlling the addition of P and B, and then isothermal heat-treatments were conducted at 550 °C and 650 °C for 3 h on these steels to make ferrite–pearlite-based or ferrite–bainite-based microstructures, respectively. B was added for controlling the reduction in toughness due to grain boundary segregation of P because B was readily distributed on grain boundaries. In the 550 °C-treated steels, bainite grains were refined by the B addition, whereas the 650 °C-treated steels did not show the grain refinement due to the B addition. According to the critical time analysis for non-equilibrium grain boundary segregation of P and B, the present isothermal treatment time of 3 h was too short for the grain boundary segregation of P, and thus the fracture occurred mostly in a cleavage mode, instead of an intergranular mode. Since this 3 h-treatment time was too long for the grain boundary segregation of B, the grain boundary segregation of B was reduced, and the precipitation of cementites was promoted. In the 550 °C-treated steels, the area fraction of intergranular fracture increased with increasing volume fraction of grain boundary cementites, as they played an important role in initiating the intergranular fracture, although the area fraction of intergranular fracture was lower than 5%. In the 650 °C-treated steels having coarse grains, however, grain boundary cementites did not work for intergranular fracture because the crack readily propagated in a cleavage mode.

  2. Material properties characterization of low carbon steel using TBW and PWHT techniques in smooth-contoured and U-shaped geometries

    International Nuclear Information System (INIS)

    This paper investigates the effects of the temper bead welding (TBW) technique and post weld heat treatment (PWHT) on mechanical properties of multi-layer welding on low carbon steel specimens using Charpy V-notch impact testing and tensile testing. Several samples of two different weld geometries, viz. (i) smooth-contoured, and (ii) U-shaped were made with multiple bead layers using both TBW and PWHT techniques. Impact testing showed that at room temperature and below, TBW gave an impact toughness in the Heat Affected Zone (HAZ) better than both PWHT and the parent material. At temperatures higher than the room temperature but below 60 °C, PWHT gave better impact toughness in the HAZ. Above 60 °C, both TBW and PWHT showed impact toughness lower than that of the parent material. In tensile testing, both TBW and PWHT weld metal specimens produced acceptable results; however, TBW gave yield and tensile strengths closer to that of the actual material than PWHT. -- Highlights: • Effects of post weld heat treatment (PWHT) and temper bead welding (TBW) on properties are tested. • Charpy V-notch impact and tensile testing was performed on multi-layer welding of low carbon steel. • At room temperature and below, TBW gave better impact toughness than both PWHT and parent material. • Above room temperature but below 60 °C, PWHT gave better impact toughness than TBW. • Above 60 °C, both TBW and PWHT showed impact toughness lower than that of parent material

  3. A mechanical property and stress corrosion evaluation of VIM-ESR-VAR work strengthened and direct double aged Inconel 718 bar material

    Science.gov (United States)

    Montano, J. W.

    1986-01-01

    Presented are the mechanical properties and the stress corrosion resistance of triple melted vacuum induction melted (VIM), electro-slag remelted (ESR), and vacuum arc remelted (VAR), solution treated, work strengthened and direct double aged Inconel 718 alloy bars 4.00 in. (10.16) and 5.75 in. (14.60 cm) diameter. Tensile, charpy v-notched impact, and compact tension specimens were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 220 ksi (1516.85 MPa) and 200 ksi (1378.00 MPa) respectively, were realized at ambient temperature. Additional charpy impact and compact tension tests were performed at -100 F (-73 C). Longitudinal charpy impact strength equalled or exceeded 12.0 ft-lbs (16.3 Joules) at ambient and at -100 F(-73 C) while longitudinal compact (LC) tension fracture toughness strength remained above 79 ksi (86.80 MPa) at ambient and at -100 F(-73 C) temperatures. No failures occurred in the longitudinal or transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test indicated no mechanical property degradation.

  4. Influence of Mo addition on the tempered properties of 13Cr martensitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Byong Ho; Ahn, Yong Sik [Pukyong National Univ., Busan (Korea, Republic of)

    1998-11-01

    In order to investigate the effect of Mo addition on the mechanical properties of 13Cr-0.2C martensitic stainless steel, tensile test and Charpy V-notch test were performed after tempering at the temperature range of 200{approx}700 .deg. C following austenitizing at 1100 .deg. C. The yield strength and hardness of the steel were increased with the increase of Mo content at all tempering conditions, because Mo causes retardation of precipitation and coarsening of carbides and solid solution strengthening of matrix. Except 500 .deg. C of tempering temperature, the Charpy impact energy was significantly increased with Mo content and showed the highest value at 1.5 wt% addition. The increase of impact energy of the steel containing Mo is thought to be caused by {delta}-ferrite formed in the tempered martensitic matrix. At 500 .deg. C tempering, Charpy impact energy was decreased drastically due to temper embrittlement and it was not possible to prevent it even though Mo was added up to 1.5 wt%.

  5. Fracture-Toughness Analysis in Transition-Temperature Region of Three American Petroleum Institute X70 and X80 Pipeline Steels

    Science.gov (United States)

    Shin, Sang Yong; Woo, Kuk Je; Hwang, Byoungchul; Kim, Sangho; Lee, Sunghak

    2009-04-01

    The fracture toughness in the transition-temperature region of three American Petroleum Institute (API) X70 and X80 pipeline steels was analyzed in accordance with the American Society for Testing and Materials (ASTM) E1921-05 standard test method. The elastic-plastic cleavage fracture toughness ( K Jc ) was determined by three-point bend tests, using precracked Charpy V-notch (PCVN) specimens; the measured K Jc values were then interpreted by the three-parameter Weibull distribution. The fracture-toughness test results indicated that the master curve and the 98 pct confidence curves explained the variation in the measured fracture toughness well. The reference temperatures obtained from the fracture-toughness test and index temperatures obtained from the Charpy impact test were lowest in the X70 steel rolled in the two-phase region, because this steel had smaller effective grains and the lowest volume fraction of hard phases. In this steel, few hard phases led to a higher resistance to cleavage crack initiation, and the smaller effective grain size led to a higher possibility of crack arrest, thereby resulting in the best overall fracture properties. Measured reference temperatures were then comparatively analyzed with the index temperatures obtained from the Charpy impact test, and the effects of microstructures on these temperatures were discussed.

  6. Impact

    NARCIS (Netherlands)

    Lohse, Detlef; Bergmann, Raymond; Mikkelsen, Rene; Zeilstra, Christiaan; Meer, van der Devaraj; Versluis, Michel

    2004-01-01

    A lot of information on impacts of solid bodies on planets has been extracted from remote observations of impact craters on planetary surfaces; experiments however with large enough impact energies as compared to the energy stored in the ground are difficult. We approach this problem by downscaled e

  7. The Effect of Constant and Pulsed Current Gas Tungsten Arc Welding on Joint Properties of 2205 Duplex Stainless Steel to 316L Austenitic Stainless Steel

    Science.gov (United States)

    Neissi, R.; Shamanian, M.; Hajihashemi, M.

    2016-05-01

    In this study, dissimilar 316L austenitic stainless steel/2205 duplex stainless steel (DSS) joints were fabricated by constant and pulsed current gas tungsten arc welding process using ER2209 DSS as a filler metal. Microstructures and joint properties were characterized using optical and electron scanning microscopy, tensile, Charpy V-notch impact and micro-hardness tests, and cyclic polarization measurements. Microstructural observations confirmed the presence of chromium nitride and delta ferrite in the heat-affected zone of DSS and 316L, respectively. In addition, there was some deviation in the austenite/ferrite ratio of the surface welding pass in comparison to the root welding pass. Besides having lower pitting potential, welded joints produced by constant current gas tungsten arc welding process, consisted of some brittle sigma phase precipitates, which resulted in some impact energy reduction. The tensile tests showed high tensile strength for the weld joints in which all the specimens were broken in 316L base metal.

  8. Toughness testing and high-temperature oxidation evaluations of advanced alloys for core internals

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Lizhen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chen, Xiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-16

    In summary, Alloy X-750 was procured from Carpenter Technology and Bodycote in this year. An appropriate TMT was developed on Alloy 439 to obtain materials with refined grain size for property screening tests. Charpy V-notch impact tests were completed for the three ferritic steels Grade 92, Alloy 439, and 14YWT. Fracture toughness tests at elevated temperatures were completed for 14YWT. The tests will be completed for the other alloys in next fiscal year. Steam oxidation tests of the three ferritic steels, 316L, and Zr–2.5Nb have been completed. The steam tests of the Ni-based superalloys and the other austenitic stainless steels will be continued and finished in next fiscal year. Performance ranking in terms of steam oxidation resistance and impact/fracture toughness of the alloys will be deduced.

  9. Prediction of Mechanical Properties of 25CrMo48V Seamless Tube Using Neural Network Model

    Science.gov (United States)

    Sun, Laibo; Zhang, Chuanyou; Wang, Qingfeng; Wang, Mingzhi; Yan, Zesheng

    In this investigation, a neural network model was established to predict mechanical properties of 25CrMo48V seamless tubes. The sensitivity analysis was also performed to estimate the relative significance of each chemical composition in mechanical behavior of steel tubes. The results of this investigation show that there is a good agreement between experimental and predicted values indicating desirable validity of the model. Among those alloying elements, the elements of carbon, silicon and chromium tended to play a more important role in controlling both the yielding strength and the Charpy-V-Notch transverse impact toughness. In comparison, the impurities such as O, N, S and P have a relatively weak impact. More detailed dependences of mechanical properties on each chemical composition in isolation can be revealed using the established model. The well-trained neural network has a great potential in designing tough and ultrahigh-strength seamless tubes and modeling the on-line production parameters.

  10. Design of a low-alloy high-strength and high-toughness martensitic steel

    Science.gov (United States)

    Zhao, Yan-jun; Ren, Xue-ping; Yang, Wen-chao; Zang, Yue

    2013-08-01

    To develop a high strength low alloy (HSLA) steel with high strength and high toughness, a series of martensitic steels were studied through alloying with various elements and thermodynamic simulation. The microstructure and mechanical properties of the designed steel were investigated by optical microscopy, scanning electron microscopy, tensile testing and Charpy impact test. The results show that cementite exists between 500°C and 700°C, M7C3 exits below 720°C, and they are much lower than the austenitizing temperature of the designed steel. Furthermore, the Ti(C,N) precipitate exists until 1280°C, which refines the microstructure and increases the strength and toughness. The optimal alloying components are 0.19% C, 1.19% Si, 2.83% Mn, 1.24% Ni, and 0.049% Ti; the tensile strength and the V notch impact toughness of the designed steel are more than 1500 MPa and 100 J, respectively.

  11. The Influence of Heat Treatment on the Microstructure and Machinability of a Prehardened Mold Steel

    Science.gov (United States)

    Hoseiny, Hamed; Caballero, Francisca G.; M'Saoubi, Rachid; Högman, Berne; Weidow, Jonathan; Andrén, Hans-Olof

    2015-05-01

    The machinability performance of a modified AISI P20 steel, heat treated to have the same hardness but three different microstructures, lower bainite, tempered martensite, and primary spheroidized carbides in a tempered martensite matrix, was studied. The microstructures were characterized using light optical and scanning electron microscopy and X-ray diffraction, and mechanical properties were compared by means of tensile and Charpy V-notch impact tests. The influence of microstructure and the resultant mechanical properties on machinability was studied in the context of single tooth end milling operation. The results showed that the material containing primary spheroidized carbides exhibited a superior machinability at the expense of a marginal loss of tensile strength and impact toughness, with comparable yield strength to that of the material containing tempered martensite. By contrast, the material with bainitic microstructure showed the lowest yield strength and the poorest machinability performance while having the highest uniform elongation.

  12. Factors affecting miniature Izod impact strength of tungsten-fiber-metal-matrix

    Science.gov (United States)

    Winsa, E. A.; Petrasek, D. W.

    1973-01-01

    The miniature Izod and Charpy impact strengths of copper, copper-nickel, and nickel-base superalloy uniaxially reinforced with continuous tungsten fibers were studied. In most cases, impact strength was increased by increasing fiber or matrix toughness, decreasing fibermatrix reaction, increasing test temperature, hot working, or heat treating. Notch sensitivity was reduced by increasing fiber content or matrix toughness. An equation relating impact strength to fiber and matrix properties and fiber content was developed. Program results imply that tungsten alloy-fiber/superalloy matrix composites can be made with adequate impact resistance for turbine blade or vane applications.

  13. Properties of the heat affected zone of a Nb microalloyed steel

    International Nuclear Information System (INIS)

    The weld thermal cycles and stress relieve heat treatment influences on multipass welds, by shielded metal arc welding process (SMAW), were evaluated in the heat affected zone of a Nb microalloyed steel, through Charpy-V notch tests, hardness measurements and microstructural aspects. (Author)

  14. Plastic fracture toughness of austenitic welding connection for Ver-1000 nuclear reactor piping of 300-350 mm diameter

    International Nuclear Information System (INIS)

    The outside welding technology for circular welds in a pearlitic tube using austenitic welding wire materials is developed and applied in manufacturing pipelines of CPP and ECC. Mechanical properties and fracture toughness of austenitic welded joints in pearlitic tubes are determined to substantiate by calculation the practicality of the leakage prior to failure concept. The work is accomplished on experimental tube manufactured by hand arc welding. When manufactured the tube is cut into 5 rings. From the rings the tensile specimens are cut for testing at 20 and 350 deg C as well as Charpy V-notch impact specimens and compact specimens ST-1T. It is shown that the materials of the experimental tube meet the standard requirements. Only axial specimens cut across the weld are not in conformity with the requirements for specific elongation

  15. Advanced-gas-cooled-nuclear-reactor materials evaluation and development program. Volume 1.Final report, September 23, 1976-September 30, 1982

    International Nuclear Information System (INIS)

    Included in this report is a discussion of the materials selected for the screening phase and more intensive screening phase test programs and the systems and components for which they are candidate materials. Thirty-one (31) commercially available alloy and alloy/coating materials and ten (10) experimental alloys were evaluated in the program. The experimental test facilities developed as part of this program are discussed and experimental testing procedures are summarized. The results of the initial screening test programs are presented. This includes creep testing results and metallographic analyses of candidate materials exposed to simulated HTGR helium and air under stress at temperatures of 7500, 8500, 9500, or 10500C (13820, 15620, 17420, or 19220F) for exposure times to 10,000 hours. Metallographic analyses, weight change and carbon analyses results, and post exposure room temperature tensile and Charpy V-notch impact test results are presented for candidate materials exposed unstressed under the conditions stated above

  16. Verification of the effect of surface preparation on Hot Isostatic Pressing diffusion bonding joints of CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yanyun [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Li, Chunjing, E-mail: chunjing.li@fds.org.cn [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Bo; Liu, Shaojun [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Qunying [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2014-12-15

    Hot Isostatic Pressing (HIP) diffusion bonding with CLAM steel is the primary candidate fabrication technique for the first wall (FW) of DFLL-TBM. Surface state is one of the key factors for the joints quality. The effect of surface state prepared with grinder and miller on HIP diffusion bonding joints of CLAM steel was investigated. HIP diffusion bonding was performed at 140 MPa and 1373 K within 3 h. The mechanical properties of the joints were investigated with instrumented Charpy V-notch impact tests and the microstructures of the joints were analyzed with scanning electron microscopy (SEM). The results showed that the milled samples with fine surface roughness were more suitable for CLAM steel HIP diffusion bonding.

  17. Verification of the effect of surface preparation on Hot Isostatic Pressing diffusion bonding joints of CLAM steel

    Science.gov (United States)

    Zhao, Yanyun; Li, Chunjing; Huang, Bo; Liu, Shaojun; Huang, Qunying

    2014-12-01

    Hot Isostatic Pressing (HIP) diffusion bonding with CLAM steel is the primary candidate fabrication technique for the first wall (FW) of DFLL-TBM. Surface state is one of the key factors for the joints quality. The effect of surface state prepared with grinder and miller on HIP diffusion bonding joints of CLAM steel was investigated. HIP diffusion bonding was performed at 140 MPa and 1373 K within 3 h. The mechanical properties of the joints were investigated with instrumented Charpy V-notch impact tests and the microstructures of the joints were analyzed with scanning electron microscopy (SEM). The results showed that the milled samples with fine surface roughness were more suitable for CLAM steel HIP diffusion bonding.

  18. Standard Guide for In-Service Annealing of Light-Water Moderated Nuclear Reactor Vessels

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This guide covers the general procedures to be considered for conducting an in-service thermal anneal of a light-water moderated nuclear reactor vessel and demonstrating the effectiveness of the procedure. The purpose of this in-service annealing (heat treatment) is to improve the mechanical properties, especially fracture toughness, of the reactor vessel materials previously degraded by neutron embrittlement. The improvement in mechanical properties generally is assessed using Charpy V-notch impact test results, or alternatively, fracture toughness test results or inferred toughness property changes from tensile, hardness, indentation, or other miniature specimen testing (1). 1.2 This guide is designed to accommodate the variable response of reactor-vessel materials in post-irradiation annealing at various temperatures and different time periods. Certain inherent limiting factors must be considered in developing an annealing procedure. These factors include system-design limitations; physical constrain...

  19. A Study on the Low Temperature Brittleness by Cyclic Cooling-Heating of Low Carbon Hot Rolled Steel Plate

    International Nuclear Information System (INIS)

    The ductile-brittle transition phenomenon of low carbon steel has been investigated using the standard Charpy V-notch specimen. Dry ice and acetone were used as refrigerants. Notched specimens were cut from the hot rolled plate produced at POSCO for the Olsen impact test. The effect of cyclic cooling and heating of 0.14% carbon steel on the embrittlement was extensively examined. The ductile-brittle transition temperature was found to be approximately-30 .deg. C. The transition temperature was gradually increased as the number of cooling-heating cycles increased. On a typical V-notch fracture surface it was found that the ductile fracture surface showed a thick and fibrous structure, while the brittle fracture surface a small and light grain with irregular disposition. As expected, the transition temperature was also increased as the carbon content of steel increased. Compared with the case of 0.14% carbon steel, the transition temperature of 0.17% carbon steel was found to be increased about 12 .deg. C

  20. Impacts

    NARCIS (Netherlands)

    Hellmuth, M.; Kabat, P.

    2003-01-01

    Even without the impacts of climate change, water managers face prodigious challenges in meeting sustainable development goals. Growing populations need affordable food, water and energy. Industrial development demands a growing share of water resources and contaminates those same resources with its

  1. IMPACTS !

    CERN Multimedia

    2008-01-01

    (Photo courtesy of Don Davis / NASA)The University of Geneva (UNIGE) and the Ecole Polytechnique Fédérale of Lausanne (EPFL) are organising the 4th series of public lectures on astronomy, on the theme of "Impacts". The schedule is as follows: Il y a 100 ans : une explosion dans la Tunguska – Dr. Frédéric COURBIN, EPFL Les impacts sur Terre – Prof. Didier Queloz, UNIGE La fin des dinosaures – Dr. Stéphane Paltani, UNIGE Wednesday 7 May 2008, from 7.00 p.m. to 9.00 p.m. Auditoire CO1, EPFL, Ecublens Thursday 08 May 2008, from 7.00 p.m. to 9.00 p.m. Auditoire Rouiller, Uni-Dufour, Genève All 3 lectures will be givent each evening! Admission free Information: 022 379 22 00

  2. Tensile and impact properties of the steel MANET-II and their optimization

    International Nuclear Information System (INIS)

    The report describes the investigations concerning tensile and impact bending properties done in the IMF-II of the KfK. The tensile tests include the investigation of the parameters test temperature, deformation rate, specimen site, cast, dimensions of the semi finished products and other parameters. The material has an adequate strength (e.g. Rp0,2 (500 C) = 465 MPa), a sufficient ductility (e.g. A > 10%) and a good homogenity of this properties. The impact bending properties of some heats of the MANET-II grade steel had been investigated using instrumented V-notch impact bending tests, and it has been compared with other steels. The strength of the MANET-II grade steel, measured by the maximum load and the stress intensity factor, is very high. The ductility, measured by the specimen bending up to the cleavage fracture, is sufficient. The toughness of the material, measured by the upper shelf energy of the impact strength, by the energy up to the maximum load and by the J-integral, is adequate. Only the transition temperature of the impact energy (DBTT = 0 C) and the FATT (T = +4 C) are too high. The limiting temperature of the first or last appearance of cleavage fracture is too high, too. For that reason an optimization of the thermal treatment of the steel had been attempted. That leads to a higher yield strength at elevated temperature and to a lower DBTT = -30 C. (orig.)

  3. Evaluation of Crashworthiness for SAE Materials under Ductile to Brittle Transition Temperature (DBTT

    Directory of Open Access Journals (Sweden)

    Amol Bhanage

    2014-10-01

    Full Text Available The concept of crashworthy coaches came into existence after a crash. This demands, avoid vehicle deformation of other/central parts. For this, the behaviour of plastic deformation of the material is necessary to be known. So, these results are required to study the crashworthy behaviour of the structure. In this research, Comparative study has been taken on the automotive materials of SAE 1026, SAE 4140, SAE 5120 and SAE8620. This paper presents the results of fracture toughness, impact energy and stress required for crack propagation from Charpy v-notch impact test and tensile test. The mechanical behaviour of SAE 1026, SAE 4140, SAE 5120 and SAE 8620 are important to describe response during actual loading condition properties used in the crash analysis of the component. The Charpy impact test was conducted at temperature ranging from room temperature 24°C, 0°C, -20°C, - 40°C, -60°C. Specimens oriented in T-L direction are tested. The materials SAE 1026, SAE 4140, SAE 5120 and SAE8620 shown that the ductile to brittle transition temperature, based on 19.5 J, 10.5 J, 113 J, 59.5 J, absorbed energy is about 1.2°C, -3°C, -38°C, -10°C respectively.

  4. Long term aging of duplex stainless steels. Relationship between toughness properties and metallurgical parameters

    International Nuclear Information System (INIS)

    The long term thermal aging behaviour of a whole series of Molybdenum-bearing and Molybdenum-free heats of cast duplex stainless steels has been studied between 300 and 400 deg C. It has been characterized mainly through the evolution of hardness, microhardness of the ferrite, impact Charpy toughness, Charpy-V notch transitions curves and in some cases in term of resistance to ductile tearing with the aim of establishing predictive knowledge from which the behaviour of real components can be assessed. The large data base collected in this extended programme has allowed to show the influence of metallurgical parameters (in particular ferrite, Cr, Ni, Mo contents, ferrite morphology or final solution heat treatment) on mechanical properties in unaged conditions and after aging. For given Cr and ferrite content, Mo-free heats (having also lower nickel content) age considerably less than Mo-bearing heats at 350 deg C, but tend towards the same behaviour at 400 deg C. The analysis of aging kinetics (from the evolution of impact toughness) for Mo-bearing heats (most sensitive to aging) allowed to deduce a set of apparent activation energies which decrease with increasing aging temperature. With this time-temperature equivalence parameter, extrapolations and predictive toughness curves can be given

  5. Correlation of microstructure and fracture properties of API X70 pipeline steels

    Science.gov (United States)

    Hwang, Byoungchul; Kim, Young Min; Lee, Sunghak; Kim, Nack J.; Ahn, Seong Soo

    2005-03-01

    Effects of microstructure on fracture toughness and transition temperature of high-toughness X70 pipeline steels were investigated in this study. Three types of steels were fabricated by varying alloying elements such as C, Cu, and Mo, and their microstructures were varied by rolling conditions such as finish rolling temperature and finish cooling temperature. Charpy V-notch (CVN) impact tests and pressed notch drop-weight tear tests (DWTT) were conducted on the rolled steel specimens. The charpy impact test results indicated that the specimens rolled in the single-phase region of the steel containing a reduced amount of C and Mo had the highest upper shelf energy (USE) and the lowest energy transition temperature (ETT) because of the appropriate formation of acicular, quasipolygonal, or polygonal ferrite and the decreased fraction of martensite-austenite constituents. Most of the specimens rolled in the single-phase region also showed excellent DWTT properties as the percent shear area (pct SA) well exceeded 85 pct, irrespective of finish cooling temperatures, while their USE was higher than that of the specimens rolled in the two-phase region. Thus, overall fracture properties of the specimens rolled in the single-phase region were better than those of the specimens rolled in the two-phase region, considering both USE and pct SA.

  6. Impact tests of the tungsten coated stainless steels prepared by using magnetron sputtering with ion beam mixing or electron beam alloying treatment

    International Nuclear Information System (INIS)

    Tungsten films were deposited on stainless steel (SS) with ion beam mixing (IBM) or electron beam alloying (EBA) treatment. The ductile–brittle transition behaviors of the specimens were investigated by means of instrumented Charpy impact test at a series of temperature, and SEM was used to observe the morphology of the cross section. Impact tests show that different treatment methods with W films do not have much influence on crack initiation, while EBA treatment with W films can more effectively prevent crack propagation, namely improve the impact toughness of SS than using IBM treatment. The reason that caused this difference was discussed

  7. Impact tests of the tungsten coated stainless steels prepared by using magnetron sputtering with ion beam mixing or electron beam alloying treatment

    Science.gov (United States)

    Zou, Yu; Zhan, Chang-Yong; Yang, Bin; Wu, Jian-Chun

    2013-05-01

    Tungsten films were deposited on stainless steel (SS) with ion beam mixing (IBM) or electron beam alloying (EBA) treatment. The ductile-brittle transition behaviors of the specimens were investigated by means of instrumented Charpy impact test at a series of temperature, and SEM was used to observe the morphology of the cross section. Impact tests show that different treatment methods with W films do not have much influence on crack initiation, while EBA treatment with W films can more effectively prevent crack propagation, namely improve the impact toughness of SS than using IBM treatment. The reason that caused this difference was discussed.

  8. Impact tests of the tungsten coated stainless steels prepared by using magnetron sputtering with ion beam mixing or electron beam alloying treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Yu; Zhan, Chang-Yong; Yang, Bin [Key Lab. For Radiation Physics and Technology of Education Ministry of China, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); Wu, Jian-Chun, E-mail: jcwu@scu.edu.cn [Key Lab. For Radiation Physics and Technology of Education Ministry of China, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China)

    2013-05-15

    Tungsten films were deposited on stainless steel (SS) with ion beam mixing (IBM) or electron beam alloying (EBA) treatment. The ductile–brittle transition behaviors of the specimens were investigated by means of instrumented Charpy impact test at a series of temperature, and SEM was used to observe the morphology of the cross section. Impact tests show that different treatment methods with W films do not have much influence on crack initiation, while EBA treatment with W films can more effectively prevent crack propagation, namely improve the impact toughness of SS than using IBM treatment. The reason that caused this difference was discussed.

  9. Effects of radiation on crack-initiation and crack-arrest toughness for SA508 Cl. 3 steel

    International Nuclear Information System (INIS)

    An investigation was carried out to determine the effects of neutron irradiation, conducted in several different test-reactors at approximately 280 C, on the mechanical properties of an SA508 Class 3 carbon steel ring forging produced in Italy as a prototype of a pressurized water reactor vessel. The research had two primary objectives: (1) to investigate the effect of a various levels of neutron irradiation (fluences from 1 to 5.5 1019 n/cm2 [E>1 MeV]) on the strength, initiation and arrest toughness and ductile-to-brittle transition temperature, and (2) to determine if Charpy data and empirical prediction equations provide conservative estimates of irradiation effects on the KIc and KIa transition curves. The paper reports results from tension, Charpy V-notch (CVN) fracture toughness, and crack-arrest tests performed on both unirradiated and irradiated material. It was found that both Charpy V-notch transition temperature shifts and two prediction equations provided conservative estimates of shifts in fracture initiation and fracture arrest transition temperatures for the steel investigated. The 54 C shift of the Charpy V-notch transition curves at a fluence level of 5.5 1019 n/cm2 suggests the possibility of extending the component life beyond the common 40 year design life

  10. Procedure of crack resistance estimation for steels from results of standard tensile and impact bend tests

    International Nuclear Information System (INIS)

    Dependences binding minimal level of the static crack resistance, yield point and reduced test temperature Ttest-TB50 are plotted according to the results obtained from test of various structural steels. The given dependences permit suggesting a simple method to calculate static crack resistance by the yield point of steel and critical temperature, corresponding to 50 % viscous component in the fracture of standard impact specimens of the Charpy type. This method has been used to calculate temperature dependences of crack resistance and choice of optimal composition for cold-resistant cast steel

  11. The effect of heat treatment on the hardness and impact properties of medium carbon steel

    Science.gov (United States)

    Mazni Ismail, Noor; Khatif, Nurul Aida Amir; Aliff Kamil Awang Kecik, Mohamad; Hanafiah Shaharudin, Mohd Ali

    2016-02-01

    This paper covers the effect of heat treatment on the mechanical properties of medium carbon steel. The main objective of this project is to investigate the hardness and impact properties of medium carbon steel treated at different heat treatment processes. Three types of heat treatment were performed in this project which are annealing, quenching and tempering. During annealing process, the specimens were heated at 900°C and soaked for 1 hour in the furnace. The specimens were then quenched in a medium of water and open air, respectively. The treatment was followed by tempering processes which were done at 300°C, 450°C, and 600°C with a soaking time of 2 hours for each temperature. After the heat treatment process completed, Rockwell hardness test and Charpy impact test were performed. The results collected from the Rockwell hardness test and Charpy impact test on the samples after quenching and tempering were compared and analysed. The fractured surfaces of the samples were also been examined by using Scanning Electron Microscope. It was observed that different heat treatment processes gave different hardness value and impact property to the steel. The specimen with the highest hardness was found in samples quenched in water. Besides, the microstructure obtained after tempering provided a good combination of mechanical properties due to the process reduce brittleness by increasing ductility and toughness.

  12. To improve impact damage response of single and multi-delaminated FRP composites using natural Flax yarn

    International Nuclear Information System (INIS)

    Highlights: ► To study the impact resistance of delaminated composite structures. ► To improve the impact resistance of delaminated composite structures using natural Flax yarn. ► To investigate the effect of z-pinning on the damage process of composite materials. ► To develop FE techniques to model the impact process of composite structures using LSDYNA. -- Abstract: The ply delamination which is known as a principle mode of failure of layered composites due to separation along the interfaces of the layers is one of the main concerns in designing of composite material structures. In this regard, the effect of hybrid laminate lay-up in multi-delaminated composite beam was investigated. The Charpy impact test was chosen to study the energy absorbing capability of delaminated composite beam. Hybrid composite beams were fabricated from combination of glass/epoxy and carbon/epoxy composites. To improve the impact behaviour of multi-delaminated composite beams the laminated hybrid composite beams were pinned using Flax yarns before curing process. It was shown that the multi-delaminated composite beams which are pinned in z-direction are able to arrest the crack propagation and consequently absorb more energy in comparison with simple ones in hybrid composite beams. The Charpy impact test of delaminated composite beams was also simulated by finite element software LS-DYNA and the results were verified with the relevant experimental results.

  13. Instrumented Impact Testing: Influence of Machine Variables and Specimen Position

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; McCowan, C. N.; Santoyo, R. A.

    2008-09-15

    An investigation has been conducted on the influence of impact machine variables and specimen positioning on characteristic forces and absorbed energies from instrumented Charpy tests. Brittle and ductile fracture behavior has been investigated by testing NIST reference samples of low, high and super-high energy levels. Test machine variables included tightness of foundation, anvil and striker bolts, and the position of the center of percussion with respect to the center of strike. For specimen positioning, we tested samples which had been moved away or sideways with respect to the anvils. In order to assess the influence of the various factors, we compared mean values in the reference (unaltered) and altered conditions; for machine variables, t-test analyses were also performed in order to evaluate the statistical significance of the observed differences. Our results indicate that the only circumstance which resulted in variations larger than 5 percent for both brittle and ductile specimens is when the sample is not in contact with the anvils. These findings should be taken into account in future revisions of instrumented Charpy test standards.

  14. Effects of irradiation on strength and toughness of commercial LWR vessel cladding

    International Nuclear Information System (INIS)

    The potential for stainless steel cladding to improve the fracture behavior of an operating nuclear reactor pressure vessel, particularly during certain overcooling transients, may depend greatly on the properties of the irradiated cladding. Therefore, weld overlay cladding irradiated at temperatures and to fluences relevant to power reactor operation was examined. The cladding was applied to a pressure vessel steel plate by the three-wire series-arc commercial method. Cladding was applied in three layers to provide adequate thickness for the fabrication of test specimens. The three-wire series-arc procedure, developed by Combustion Engineering, Incl, Chattanooga, Tennessee, produced a highly controlled weld chemistry, microstructure, and fracture properties in all three layers of the weld. Charpy V-notch and tensile specimens were irradiated at 288 deg. C to fluence levels of 2 and 5x1019 neutrons/cm2 (>1 MeV). Postirradiation testing results show that, in the test temperature range from -125 to 288 deg. C, the yield strength increased by 8 to 30%, ductility insignificantly increased, while there was almost no change in ultimate tensile strength. All cladding exhibited ductile-to-brittle transition behavior during Charpy impact testing, due to the dominance of delta-ferrite failures at low temperatures. On the upper shelf, energy was reduced, due to irradiation exposure, 15 to 20%, while the lateral expansion was reduced 43 to 41%, at 2 and 5x1019 neutrons/cm2 (>1 MeV), respectively. In addition, radiation damage resulted in 13 and 28 deg. C shifts of the Charpy impact transition temperature at the 41-J level for the low and high fluences, respectively. (author)

  15. Mechanical properties of 1950's vintage 304 stainless steel weldment components after low temperature neutron irradiation

    International Nuclear Information System (INIS)

    The reactor vessels of the nuclear production reactors at the Savannah River Site (SRS) were constructed in the 1950's from Type 304 stainless steel plates welded with Type 308 stainless steel filler using the multipass metal inert gas process. An irradiated mechanical properties database has been developed for the vessel with materials from archival primary coolant system piping irradiated at low temperatures (75 to 150 degrees C) in the State University of New York at Buffalo reactor (UBR) and the High Flux Isotope Reactor (HFIR) to doses of 0.065 to 2.1 dpa. Fracture toughness, tensile, and Charpy-V impact properties of the weldment components (base, weld, and weld heat-affected-zone (HAZ)) have been measured at temperatures of 25 degrees C and 125 degrees C in the L-C and C-L orientations for materials in both the irradiated and unirradiated conditions for companion specimens. Fracture toughness and tensile properties of specimens cut from an SRS reactor vessel sidewall with doses of 0.1 and 0.5 dpa were also measured at temperatures of 25 and 125 degrees C. The irradiated materials exhibit hardening with loss of work hardenability and a reduction in toughness relative to the unirradiated materials. The HFIR-irradiated materials show an increase in yield strength between about 20% and 190% with a concomitant tensile strength increase between about 15% to 30%. The elastic-plastic fracture toughness parameters and Charpy-V energy absorption both decrease and show only a slight sensitivity to dose. The irradiation-induced decrease in the elastic-plastic fracture toughness (Jdef at 1 mm crack extension) is between 20% to 65%; the range of J1C values are 72.8 to 366 kJ/m2 for the irradiated materials. Similarly, Charpy V-notch results show a 40% to 60% decrease in impact energies

  16. Soil Erosion and Surface Water Quality Impacts of Natural Gas Development in East Texas, USA

    Directory of Open Access Journals (Sweden)

    Matthew McBroom

    2012-11-01

    Full Text Available Due to greater demands for hydrocarbons and improvements in drilling technology, development of oil and natural gas in some regions of the United States has increased dramatically. A 1.4 ha natural gas well pad was constructed in an intermittent stream channel at the Alto Experimental Watersheds in East Texas, USA (F1, while another 1.1 ha well pad was offset about 15 m from a nearby intermittent stream (F2. V-notch weirs were constructed downstream of these well pads and stream sedimentation and water quality was measured. For the 2009 water year, about 11.76 cm, or almost 222% more runoff resulted from F1 than F2. Sediment yield was significantly greater at F1, with 13,972 kg ha−1 yr−1 versus 714 kg ha−1yr−1 at F2 on a per unit area disturbance basis for the 2009 water year. These losses were greater than was observed following forest clearcutting with best management practices (111–224 kg ha−1. Significantly greater nitrogen and phosphorus losses were measured at F1 than F2. While oil and gas development can degrade surface water quality, appropriate conservation practices like retaining streamside buffers can mitigate these impacts.

  17. Irradiation damage behavior of low alloy steel wrought and weld materials

    International Nuclear Information System (INIS)

    A study was undertaken to evaluate the irradiation damage response of several different types of low alloy steel. The materials included vitange type ASTM A302 Grade B (A302B) plates and welds containing different nickel (Ni) and copper (Cu) concentrations, 3.5% Ni steels similar to ASTM A508 Class 4, welds containing about 1% Ni (similar to type 105S), and 3.5% Ni steels with 'superclean' composition (extremely low phosphorus, sulfur, manganese and silicon). To determine irradiation damage behavior, all materials were irradiated at several different irradiation damage levels ranging from 0.0003 dpa to 0.06 dpa at an irradiation damage levels ranging from 0.003 dpa to 0.06 dpa at an irradiation temperature of about 232 degrees C (450 degrees F). Complete Charpy V-notch impact energy transition temperature curves were generated for all materials before and after irradiation to determine the transition temperature at 41J (30 ft-lb) or 47J (35 ft-lb) and the upper shelf energy. The irradiation damage behavior was measured by the shift in the Charpy 41J or 47J transition temperature (ΔTT41J or ΔTT47J) and lowering of the upper shelf Charpy energy at a given irradiation damage level. It was found that chemical composition greatly influenced irradiation damage behavior. The highest irradiation damage (greatest ΔTT) was found in an A302B type weld contaiNing 1.28% Ni and 0.20% CU while the least irradiation damage was found in the 3.5% Ni, 0.05% Cu, superclean wrought materials

  18. Consideration of neutron flux gradients for sophisticated evaluation of irradiation experiments

    International Nuclear Information System (INIS)

    A joint Russian/German irradiation experiment was performed at the pressurised water reactor WWER 2 of the Rheinsberg NPP (Germany). The experiment comprises about 800 Charpy V-notch, SENB and CT specimens made from 24 different heats of Russian type RPV base and weld metals. Comprehensive calculations of the neutron fluence were carried out. A multigroup Monte Carlo method allows the calculation of the neutron fluence of each specimen or of different points within a large specimen under consideration of the details of the geometric arrangement. As the calculations shown the neutron fluence considerably varies over the cross section of an irradiation rig. Therefore, influence of the flux gradients on testing of Charpy V-notch and CT-specimens is evaluated. Methods taking into account a fluence correction of the measured absorbed energies are presented and discussed. (author)

  19. The effect of low dose irradiation on the impact fracture energy and tensile properties of pure iron and two ferritic martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Belianov, I. [Central Research Inst. of Structural Materials (CRISM), St. Petersburg (Russian Federation); Marmy, P. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherches en Physique des Plasmas

    1998-10-01

    Two batches of subsize V-notched impact bend specimens and subsize tensile specimens have been irradiated in the Saphir test reactor of the Paul Scherrer Institute (PSI). The first batch of specimen has been irradiated at 250 C to a dose of 2.65 x 10{sup 19} n/cm{sup 2} (0.042 dpa) and the second batch has been irradiated at 400 C to a dose of 8.12 x 10{sup 19} n/cm{sup 2} (10.13 dpa). Three different materials in three different microstructures were irradiated: pure iron and two ferritic steels, the alloy MANET 2 and a low activation composition CETA. The results of the impact tests and of the corresponding tensile tests are presented. Despite the very low neutron dose, a significant shift of the ductile to brittle transition temperature (DBTT) is observed. The influence of the test temperature on the impact energy is discussed for the irradiated and unirradiated conditions, with special emphasis on the microstructure. (orig.) 10 refs.

  20. The effect of low dose irradiation on the impact fracture energy and tensile properties of pure iron and two ferritic martensitic steels

    International Nuclear Information System (INIS)

    Two batches of subsize V-notched impact bend specimens and subsize tensile specimens have been irradiated in the Saphir test reactor of the Paul Scherrer Institute (PSI). The first batch of specimen has been irradiated at 250 C to a dose of 2.65 x 1019 n/cm2 (0.042 dpa) and the second batch has been irradiated at 400 C to a dose of 8.12 x 1019 n/cm2 (10.13 dpa). Three different materials in three different microstructures were irradiated: pure iron and two ferritic steels, the alloy MANET 2 and a low activation composition CETA. The results of the impact tests and of the corresponding tensile tests are presented. Despite the very low neutron dose, a significant shift of the ductile to brittle transition temperature (DBTT) is observed. The influence of the test temperature on the impact energy is discussed for the irradiated and unirradiated conditions, with special emphasis on the microstructure. (orig.)

  1. Prediction of quenched and tempered steel and cast steel properties

    OpenAIRE

    B. Smoljan; D. Iljkić; H. Novak

    2011-01-01

    Purpose: The influence of processing parameters, such as pouring temperature and cooling rate during the casting, as well as application of hot working and pre-heat treatment, on strength and toughness of quenched and tempered steel was investigated.Design/methodology/approach: Strength and toughness were presented by yield strength and Charpy-V notch toughness, respectively. Experimental procedure of material properties optimization was done using the 25-2 factor experiment.Findings: It was ...

  2. Mechanical characterization based in the impact test of the cadmium-zinc and cadmium-zinc-copper alloys; Caracterizacion mecanica basada en la prueba de impacto de las aleaciones cadmio-zinc y cadmio-zinc-cobre

    Energy Technology Data Exchange (ETDEWEB)

    Casolco, S.R.; Torres V, G. [Instituto de Investigacion en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, 04510 Mexico D.F. (Mexico)

    1999-11-01

    The present work is a study carried out in the Institute for Materials Research of the UNAM, of the alloys cadmium-zinc and cadmium-zinc-copper with the fundamental objective of knowing their behavior to the impact that which will allow to establish structural applications of these alloys. This work consists mainly on impact tests of the type Charpy at different temperatures in a range of - 150 Centigrade to 250 Centigrade and to study their fracture morphologies with the help of a scanning electron microscope to recognize the tendency of the material toward the fracture of the fragile type and to determine the ductile-fragile transition. (Author)

  3. Precipitation and impact toughness of Nb–V stabilised 18Cr–2Mo ferritic stainless steel during isothermal aging

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jian, E-mail: jh595@uowmail.edu.au [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Li, Huijun [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Barbaro, Frank [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); CBMM Technology Suisse, 14, Rue du Rhone, Geneve 1204 (Switzerland); Jiang, Laizhu [Baoshan Iron and Steel Co., Ltd., Shanghai 200431 (China); Zhu, Zhixiong [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Xu, Haigang; Ma, Li [Baoshan Iron and Steel Co., Ltd., Shanghai 200431 (China)

    2014-08-26

    The effect of isothermal aging on precipitation behaviour and Charpy impact toughness of Nb–V stabilised 18Cr–2Mo ferritic stainless steel was investigated by means of Thermo-Calc prediction, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Charpy impact toughness testing. The results show that, niobium, vanadium carbides and nitrides, Fe{sub 2}Nb (Laves phase) and Cr{sub 23}C{sub 6} formed after 2 h aging at 800 °C, and the equilibrium solvus temperature of Fe{sub 2}Nb phase increases to above 750 °C, higher than the calculated temperature (730 °C) using Thermo-Calc. After isothermal aging at 750–950 °C, 2 h aging resulted in a decrease in toughness due to the formation of precipitation, especially (Nb,V)(C,N) and Fe{sub 2}Nb. When isothermally aged at 800 °C for up to 24 h, the coarsening rate of Fe{sub 2}Nb particle is much higher than that of (Nb,V)(C,N), and the impact toughness of the steel is dependent on quantity and sizes of (Nb,V)(C,N) and Fe{sub 2}Nb particles.

  4. Precipitation and impact toughness of Nb–V stabilised 18Cr–2Mo ferritic stainless steel during isothermal aging

    International Nuclear Information System (INIS)

    The effect of isothermal aging on precipitation behaviour and Charpy impact toughness of Nb–V stabilised 18Cr–2Mo ferritic stainless steel was investigated by means of Thermo-Calc prediction, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Charpy impact toughness testing. The results show that, niobium, vanadium carbides and nitrides, Fe2Nb (Laves phase) and Cr23C6 formed after 2 h aging at 800 °C, and the equilibrium solvus temperature of Fe2Nb phase increases to above 750 °C, higher than the calculated temperature (730 °C) using Thermo-Calc. After isothermal aging at 750–950 °C, 2 h aging resulted in a decrease in toughness due to the formation of precipitation, especially (Nb,V)(C,N) and Fe2Nb. When isothermally aged at 800 °C for up to 24 h, the coarsening rate of Fe2Nb particle is much higher than that of (Nb,V)(C,N), and the impact toughness of the steel is dependent on quantity and sizes of (Nb,V)(C,N) and Fe2Nb particles

  5. The effect of strain rate on the impact strength of the high-Mn steel

    Directory of Open Access Journals (Sweden)

    A. Śmiglewicz

    2015-10-01

    Full Text Available In the paper, results of impact bending tests of a high-manganese steel of Fe – 30 wt.%, Mn – 9 wt.%, Al – 0,65 wt.%, C grade are presented. The tests were carried out using a flywheel machine, suitable for dynamic stretching and impact bending tests in the range of linear velocity of the forcing element from 5 ÷ 40 m/s. The obtained test results were compared with the results of impact resistance of the studied steel determined using Charpy machine. Structural investigations were carried out using scanning transmission electron microscopy. Surfaces of fractures formed in the break point during bending tests were analyzed, and they indicate a presence of mixed transcrystalline fractures with a predominance of plastic fractures.

  6. Effect of Heat Input on Microstructure Evolution and Mechanical Properties in the Weld Heat-Affected Zone of 9Cr-2W-VTa Reduced Activation Ferritic-Martensitic Steel for Fusion Reactor

    Science.gov (United States)

    Moon, Joonoh; Lee, Chang-Hoon; Lee, Tae-Ho; Kim, Hyoung Chan

    2015-01-01

    The phase transformation and mechanical properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic steel were explored. The samples for HAZs were prepared using a Gleeble simulator at different heat inputs. The base steel consisted of tempered martensite and carbides through quenching and tempering treatment, whereas the HAZs consisted of martensite, δ-ferrite, and a small volume of autotempered martensite. The prior austenite grain size, lath width of martensite, and δ-ferrite fraction in the HAZs increased with increase in the heat input. The mechanical properties were evaluated using Vickers hardness and Charpy V-notch impact test. The Vickers hardness in the HAZs was higher than that in the base steel but did not change noticeably with increase in the heat input. The HAZs showed poor impact property due to the formation of martensite and δ-ferrite as compared to the base steel. In addition, the impact property of the HAZs deteriorated more with the increase in the heat input. Post weld heat treatment contributed to improve the impact property of the HAZs through the formation of tempered martensite, but the impact property of the HAZs remained lower than that of base steel.

  7. Static and fatigue failure of quasi brittle materials at a V-notch using a Dugdale model

    OpenAIRE

    Murer, S.; Leguillon, D.

    2009-01-01

    Abstract The prediction of crack nucleation at stress concentration points in brittle and quasi-brittle materials may generally rely on either an Irwin-like criterion, involving a critical value of the generalized stress intensity factor of the singularity associated to the stress concentration, or on cohesive zone models. Leguillon's criterion enters the first category and combines an energy condition and a stress one. Thanks to matched asymptotics procedures, the associated numer...

  8. V-Notched Bar Creep Life Prediction: GH3536 Ni-Based Superalloy Under Multiaxial Stress State

    Science.gov (United States)

    Zhang, D. X.; Wang, J. P.; Wen, Z. X.; Liu, D. S.; Yue, Z. F.

    2016-05-01

    In this study, creep experiments on smooth and circumferential V-type notched round bars were conducted in GH3536 Ni-based superalloy at 750 °C to identify notch strengthening effect in notched specimens. FE analysis was carried out, coupled with continuum damage mechanics (CDM), to analyze stress distribution and damage evolution under multiaxial stress state. The creep deformation of smooth specimens and the rupture life of both smooth and notched specimens showed good agreement between experimental results and FE analysis predictions; the creep rupture life for the notched specimen was successfully predicted via the "skeletal point" concept. Both creep damage analysis and the observed fracture morphology suggest that creep rupture started first at the root in the V-type notched specimens, and shifted to the region close to the notch root when the notch was relatively shallow compared to U-type notched specimens.

  9. V-Notched Bar Creep Life Prediction: GH3536 Ni-Based Superalloy Under Multiaxial Stress State

    Science.gov (United States)

    Zhang, D. X.; Wang, J. P.; Wen, Z. X.; Liu, D. S.; Yue, Z. F.

    2016-07-01

    In this study, creep experiments on smooth and circumferential V-type notched round bars were conducted in GH3536 Ni-based superalloy at 750 °C to identify notch strengthening effect in notched specimens. FE analysis was carried out, coupled with continuum damage mechanics (CDM), to analyze stress distribution and damage evolution under multiaxial stress state. The creep deformation of smooth specimens and the rupture life of both smooth and notched specimens showed good agreement between experimental results and FE analysis predictions; the creep rupture life for the notched specimen was successfully predicted via the "skeletal point" concept. Both creep damage analysis and the observed fracture morphology suggest that creep rupture started first at the root in the V-type notched specimens, and shifted to the region close to the notch root when the notch was relatively shallow compared to U-type notched specimens.

  10. How severe plastic deformation at cryogenic temperature affects strength, fatigue, and impact behaviour of grade 2 titanium

    Science.gov (United States)

    Mendes, Anibal; Kliauga, Andrea M.; Ferrante, Maurizio; Sordi, Vitor L.

    2014-08-01

    Samples of grade 2 Ti were processed by Equal Channel Angular Pressing (ECAP), either isolated or followed by further deformation by rolling at room temperature and at 170 K. The main interest of the present work was the evaluation of the effect of cryogenic rolling on tensile strength, fatigue limit and Charpy impact absorbed energy. Results show a progressive improvement of strength and endurance limit in the following order: ECAP; ECAP followed by room temperature rolling and ECAP followed by cryogenic rolling. From the examination of the fatigued samples a ductile fracture mode was inferred in all cases; also, the sample processed by cryogenic rolling showed very small and shallow dimples and a small fracture zone, confirming the agency of strength on the fatigue behaviour. The Charpy impact energy followed a similar pattern, with the exception that ECAP produced only a small improvement over the coarse-grained material. Motives for the efficiency of cryogenic deformation by rolling are the reduced grain size and the association of strength and ductility. The production of favourable deformation textures must also be considered.

  11. Mechanical properties of neutron irradiated vanadium alloys under liquid sodium environment

    International Nuclear Information System (INIS)

    Full text of publication follows: Vanadium alloys are candidate materials for fusion reactor blanket structural materials, but its knowledge about the mechanical properties at high temperatures during neutron irradiation is limited and there are uncertainties that may have influenced the results such as the interstitial impurity content of specimens. The objective of this study is to investigate the mechanical properties and microstructural changes of the high-purified V-4Cr-4Ti alloys, NIFS-HEAT2 during neutron irradiation. In this study, tensile test, Charpy impact test and microstructural observation were done for V-4Cr-4Ti alloys and vanadium binary alloys. Small sized tensile specimens, 1.5 Charpy V-notched specimens and TEM specimens of highly purified V-4Cr-4Ti alloys, NIFS-Heat and vanadium binary alloys were irradiated in Joyo in the temperature range from 450 deg. C to 650 deg. C with a damage level from 1 to 5 dpa. In the irradiation experiment, we have developed Na-enclosed irradiation rig in Joyo in order to equalize the irradiation temperature of large scale specimens and prevent the invasion of interstitial impurities from the circumstance in irradiation rig during irradiation for irradiation specimens. After dismantling the Na-enclosed capsule and cleaning the surface of specimens, tensile tests at room temperature, Charpy impact tests and TEM observation were performed. Irradiation hardening and reduction of ductility for NIFS-Heat alloys could be seen at 450 deg. C irradiation in tensile tests, but the destructive loss of plasticity could not be in any vanadium specimens even at 450 deg. C irradiation. Results of Charpy impact test showed that the amounts of upper shelf energy of NIFS-heat specimens irradiated at 450 deg. C and 600 deg. C were about 0.1-0.2 J at room temperature and brittle behavior could not be seen from load displacement relationship and SEM observation of fracture surface. From the TEM observation of NIFS-Heat alloys

  12. Low temperature mechanical properties, fractographic and metallographic evaluation of several alloy steels

    Science.gov (United States)

    Montano, J. W.

    1973-01-01

    The mechanical properties are presented of alloy steels, 4130, 4140, 4340, 6150, and 8740. Test specimens were manufactured from approximately 1.00 inch (2.54 cm) diameter bar stock which had been heat treated to two different hardness levels. The following mechanical tests were performed at temperatures of 80 F (+26.7 C), 0 F (-17.8 C), -100 F (-73 C), and -200 F (-129 C): (1) tensile test (Ultimate, yield, modulus, elongation, and reduction of area), (2) notched tensile test, (3) charpy V-notched impact test (impact energy), and (4) double shear strength test (ultimate and yield). The test data indicate excellent tensile strength, notched/unnotched tensile ratios, ductility, impact, and shear properties at all test temperatures, except at -200 F (-129 C) where the impact strength of the higher strength group of alloy steels, 4130 (Rc-37) and 4140 (Rc-44) decreased to approximately 9 ft. lbs. (12 joules) and 6 ft. lbs. (8 joules), respectively. Chemical, metallographic, and fractographic analyses were also performed to evaluate microstructure, microhardness and the effect of decrease in temperature on the ductile to brittle failure transition.

  13. Effect of Boron on Microstructure and Mechanical Properties of Hot-Rolled Nb-ADDED Hsla H-Section Steel

    Science.gov (United States)

    Wang, Zuocheng; Cui, Guotao; Sun, Tao; Guo, Weimin; Zhao, Xiuling; Gao, Junqing; Dong, Changxing

    In our research, boron was added into the Nb-added high strength low alloy (HSLA) H-section steels. The contents of boron added were 4ppm, 8ppm and 11ppm, respectively. The mechanical properties of H-section steels with/without boron were examined by using uniaxial tensile test and Charpy impact test (V-notch). The morphologies of the microstructure and the fracture surfaces of the impact specimens were observed by metalloscope, stereomicroscope and electron probe. The experimental results indicate that boron gives a significant increase in impact toughness, especially in low temperature impact toughness, though it leads to an unremarkable increase in strength and plasticity. For instance, the absorbed energy at -40°C reaches up to 126J from 15J by 8ppm boron addition, and the ductile-brittle transition temperature declines by 20°C. It is shown that boron has a beneficial effect on grain refinement. The fracture mechanism is transited from cleavage fracture to dimple fracture due to boron addition.

  14. Microstructures and Mechanical Properties of Laser Welding Joint of a CLAM Steel with Revised Chemical Compositions

    Science.gov (United States)

    Chen, Shuhai; Huang, Jihua; Lu, Qi; Zhao, Xingke

    2016-05-01

    To suppress the tendency to form delta ferrite in weld metal (WM) of China low activation martensitic (CLAM) steel joint, a CLAM steel with revised chemical compositions was designed. Laser welding of the CLAM steel was investigated. The microstructures of the WM and heat-affected zone were analyzed. The impact toughness of the WM was evaluated by a Charpy impact test method with three V notches. The influence of temper temperature on mechanical properties was analyzed. It was found that the delta ferrite was eliminated almost completely in laser WM of CLAM steel with revised chemical compositions which has lower tendency to form delta ferrite than original chemical compositions. The joint has higher tensile strength than the parent metal. With increasing the heat input, the impact toughness of the joint is approximatively equal with that of parent metal first and then decreases obviously. Temper treatment could effectively improve mechanical property of the joint. When the temper temperature exceeds 600 °C, the impact toughness of the joint is higher than that of the parent metal.

  15. Effect of Grain Boundary Character Distribution on the Impact Toughness of 410NiMo Weld Metal

    DEFF Research Database (Denmark)

    Divya, M.; Das, Chitta Ranjan; Chowdhury, Sandip Ghosh;

    2016-01-01

    Grain boundary character distributions in 410NiMo weld metal were studied in the as-welded, first-stage, and second-stage postweld heat treatment (PWHT) conditions, and these were correlated with the Charpy-V impact toughness values of the material. The high impact toughness values in the weld...... metal in the as-welded and first-stage PWHT conditions compared to that in the second-stage condition are attributed to the higher fraction of low-energy I pound boundaries. A higher volume fraction of retained austenite and coarser martensite after second-stage PWHT accompanied by the formation of the...... impact toughness. In addition to this, grain refinement during 4-hour PWHT in the second stage also increased the toughness of the weld metal....

  16. Toughness characterization by small specimen test technique for HIPed joints of F82H steel aiming at first wall fabrication in fusion

    Science.gov (United States)

    Kishimoto, H.; Ono, T.; Sakasegawa, H.; Tanigawa, H.; Kohno, Y.; Kohyama, A.

    2013-09-01

    Reduced activation ferritic/martensitic steels (RAFMs), such as F82H steels, have been developed as candidates of structural materials for fusion. In the design of a fusion reactor, cooling channels are built in the first wall of the blanket. One large issue is to determine how to join rectangular tubes to thin panels to fabricate the first wall. Hot Isostatic Pressing (HIPing) is a solution to solve the issue. Because of the thin HIPed walls of the channels, the specimen size for inspection of HIPed interface is limited. In the present research, Small Specimen Test Techniques (SSTT) are screened for the destructive toughness investigation technique of HIPed F82H joints. 1/3 size Charpy V-notch impact (1/3 CVN) and small punch (SP) tests are employed for the present research. The toughness of the HIPed joints is strongly affected by various surface finishing of specimens treated previous to the HIPing. In the present research, several kinds of HIPed joints were surface finished by different methods and investigated by 1/3 CVN impact test. The HIPed F82H joints had different toughness ranging from 20% to 70% of the toughness of the F82H base metal. The SP test is also available for the investigation of toughness change by the HIPing. The sensitivity of 1/3 CVN impact test against toughness change was better than the SP test, it revealed that the SP test has some limitations.

  17. Effect of tempering temperature on the microstructure and mechanical properties of a reactor pressure vessel steel

    Science.gov (United States)

    Li, C. W.; Han, L. Z.; Luo, X. M.; Liu, Q. D.; Gu, J. F.

    2016-08-01

    The microstructure and mechanical properties of reactor pressure vessel (RPV) steel were investigated after tempering at different temperatures ranging from 580 to 700 °C for 5 h. With increasing tempering temperature, the impact toughness, which is qualified by Charpy V-notch total absorbed energy, initially increases from 142 to 252 J, and then decreases to 47 J, with a maximum value at 650 °C, while the ultimate tensile strength varies in exactly the opposite direction. Comparing the microstructure and fracture surfaces of different specimens, the variations in toughness and strength with the tempering temperature were generally attributed to the softening of the bainitic ferrite, the agminated Fe3C carbides that resulted from decomposition of martensite/austenite (M/A) constituents, the precipitation of Mo2C carbides, and the newly formed M/A constituents at the grain boundaries. Finally, the correlation between the impact toughness and the volume fraction of the M/A constituents was established, and the fracture mechanisms for the different tempering conditions are explained.

  18. Heavy-section steel irradiation program. Progress report, April 1996--September 1996

    Energy Technology Data Exchange (ETDEWEB)

    Corwin, W.R.

    1997-09-01

    The Heavy-Section Steel Irradiation Program was established to quantitatively assess the effects of neutron irradiation on the material behavior of typical reactor pressure vessel (RPV) steels. During this period, fracture mechanics testing of specimens of the irradiated low upper shelf (LUS) weld were completed and analyses performed. Heat treatment of five RPV plate materials was initiated to examine phosphorus segregation effects on the fracture toughness of the heat affected zone of welds. Initial results show that all five materials exhibited very large prior austenite grain sizes as a consequence of the initial heat treatment. Irradiated and annealed specimens of LUS weld material were tested and analyzed. Four sets of Charpy V-notch (CVN) specimens were aged at various temperatures and tested to examine the reason for overrecovery of upper shelf energy that has been observed. Molecular dynamics cascade simulations were extended to 40 keV and have provided information representative of most of the fast neutron spectrum. Investigations of the correlation between microstructural changes and hardness changes in irradiated model alloys was also completed. Preliminary planning for test specimen machining for the Japan Power Development Reactor was completed. A database of Charpy impact and fracture toughness data for RPV materials that have been tested in the unirradiated and irradiated conditions is being assembled and analyzed. Weld metal appears to have similar CVN and fracture toughness transition temperature shifts, whereas the fracture toughness shifts are greater than CVN shifts for base metals. Draft subcontractor reports on precracked cylindrical tensile specimens were completed, reviewed, and are being revised. Testing on precracked CVN specimens, both quasi-static and dynamic, was evaluated. Additionally, testing of compact specimens was initiated as an experimental comparison of constraint limitations. 16 figs., 2 tabs.

  19. Tensile and impact properties of General Atomics 832864 heat of V-4Cr-4Ti alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Nowicki, L.J.; Gazda, J.; Billone, M.C.; Smith, D.L. [Argonne National Lab., IL (United States); Johnson, W.R.; Trester, P. [General Atomics, San Diego, CA (United States)

    1998-09-01

    A 1300-kg heat of V-4Cr-4Ti alloy was procured by General Atomics (GA) for the DIII-D radiative divertor program. To determine the mechanical properties of this alloy, tensile and Charpy tests were conducted on specimens prepared from pieces of 4.8-mm-thick as-rolled plates, a major product form for the DIII-D application. The tensile tests were conducted at three temperatures, 26, 280 and 380 C, the last two being the anticipated peak temperatures during DIII-D boronization and postvent bake-out, respectively. Results from these tests show that the tensile and impact properties of the 832864 heat are comparable to those of the other smaller V-(4-5)Cr-(4-5)Ti alloy heats previously developed by the US Fusion Materials Program and that scale-up of vanadium alloy production can be successfully achieved as long as reasonable process control is implemented.

  20. Ductile-to-brittle transition in a low alloy steel

    International Nuclear Information System (INIS)

    The mechanical properties of pressure vessel steel (and above all its resistance to brittle fracture) are a decisive factor in the complex safety assessment of nuclear power plants. The monitoring of neutron induced embrittlement is provided using Charpy impact tests on standard V-notch specimens due to their small size. Material's ductile-to-brittle transition temperature (DBTT) can be easily characterised using this test. However, Charpy impact energy cannot be immediately used for safety assessment, since fracture toughness is required. Some empirical formulas have been developed, but no direct relationship was still found. When the specimens are tested in the ductile-to-brittle transition region, cleavage crack initiation is preceded by ductile crack growth giving a large scatter to the values of fracture toughness and/or Charpy impact energy. Even if the cleavage initiation and propagation in steels containing isolated spheroidic carbides are qualitatively well understood, no one from existing models can explain the sharp upturn in ductile-to-brittle transition region. In the present work, French tempered bainitic steel 16MND5 (considered as equivalent to the American standard A508 Cl.3) is studied: The large fractographic analysis of CT and Charpy specimens broken in the DBTT range is undertaken to account for the evolution of cleavage fracture mechanisms. In addition to classical scanning electron microscopy, transmission electron microscopy and EBSD technique are used in order to study the propagation of cleavage crack. The classical fracture mechanics using KIc or Jc concepts can hardly describe the unstable brittle fracture in the DBTT range. Hence, the local approach, which aims to predict the fracture of any structural component using local criteria, providing that the mechanical fields in the structure are known, is used. The probability of cleavage fracture in the DBTT range is predicted using the Beremin model based on weakest link theory, e.g. 2

  1. Comparison of ductile-to-brittle transition curve fitting approaches

    Energy Technology Data Exchange (ETDEWEB)

    Cao, L.W. [School of Materials Science and Engineering, Beihang University (BUAA), Beijing 100191 (China)] [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR (United Kingdom); Wu, S.J., E-mail: wusj@buaa.edu.cn [School of Materials Science and Engineering, Beihang University (BUAA), Beijing 100191 (China); Flewitt, P.E.J. [Interface Analysis Centre, University of Bristol, Bristol BS2 8BS (United Kingdom)] [School of Physics, HH Wills Laboratory, University of Bristol, BS8 1TL (United Kingdom)

    2012-05-15

    Ductile-to-brittle transition (DBT) curve fitting approaches are compared over the transition temperature range for reactor pressure vessel steels with different kinds of data, including Charpy-V notch impact energy data and fracture toughness data. Three DBT curve fitting methods have been frequently used in the past, including the Burr S-Weibull and tanh distributions. In general there is greater scatter associated with test data obtained within the transition region. Therefore these methods give results with different accuracies, especially when fitting to small quantities of data. The comparison shows that the Burr distribution and tanh distribution can almost equally fit well distributed and large data sets extending across the test temperature range to include the upper and lower shelves. The S-Weibull distribution fit is poor for the lower shelf of the DBT curve. Overall for both large and small quantities of measured data the Burr distribution provides the best description. - Highlights: Black-Right-Pointing-Pointer Burr distribution offers a better fit than that of a S-Weibull and tanh fit. Black-Right-Pointing-Pointer Burr and tanh methods show similar fitting ability for a large data set. Black-Right-Pointing-Pointer Burr method can fit sparse data well distributed across the test temperature. Black-Right-Pointing-Pointer S-Weibull method cannot fit the lower shelf well and show poor fitting quality.

  2. Radiation damage in a high Ni weld

    International Nuclear Information System (INIS)

    WWER-1000 RPV weld metals are characterized by a high content of nickel, mostly about 1.7 mass % with content of manganese around 0.8 mass % with a very low copper content - about 0.05 mass %. In such material some late blooming phase effect should be observed during irradiation. Such typical weld material was irradiated in the experimental reactor LVR-15 in N RI Rez at the irradiation temperature 290 C degrees and at five neutron fluences from 1.5 to 9.5 *1023 m-2 (E>1 MeV). Charpy V-notch impact tests, static fracture toughness tests, tensile and hardness measurement were performed to obtain effect of neutron fluence on radiation hardening as well as embrittlement. Neutron fluence dependences of all these property changes have monotonic character but with a high neutron embrittlement exponent around 0.8. Scanning electron microscope of fracture surfaces showed no or very small portion of intercrystalline fracture. Transmission electron microscopy was performed on specimens from all neutron fluences. Only low density of black-dot damage has been observed. It is assumed that most of defect are dislocation loops. The late blooming phase which may be observed from results of mechanical properties are probably below the resolution of the used JEM-2010, i.e. 1.5 nm. (authors)

  3. TAPS pressure vessel surveillance - results and evaluation

    International Nuclear Information System (INIS)

    SA302B (nickel modified) steel cladded with stainless steel is used as the pressure vessel material for the two 210 MWe boiling water reactors of the Tarapur Atomic Power Station. Charpy V-notch impact surveillance specimens representing the pressure vessel belt-line base, weld and the heat affected zone were irradiated at the wall and shroud locations. Some of these specimens were removed after 6.5 effective full power years (EFPY) of reactor operation. The neutron fluences at the locations were 5.31 x 1017 and 4.88 x 1018 n/cm2 (E > 1 MeV). The surveillance data generated from specimens removed after 6.5 EFPY were evaluated on the basis of USNRC Regulatory Guide 1.99, Revision 2, and the results had assured the integrity of the vessel beyond the end of design service life (EOL) of 40 years. The recent evaluation of the additional data generated from specimens removed after 13 EFPY has again confirmed the safety of the pressure vessel beyond EOL by an additional 20 EFPY. (author)

  4. Mechanical properties of low alloy high phosphorus weathering steel

    Directory of Open Access Journals (Sweden)

    Jena B.K.

    2015-01-01

    Full Text Available Mechanical behaviour of two low alloy steels (G11 and G12 was studied with respect to different phosphorus contents. Tensile strength and yield strength increased while percentage elongation at fracture decreased on increasing phosphorus content. The SEM and light optical photomicrograph of low phosphorus steel (G11 revealed ferrite and pearlite microstructure. On increasing phosphorus content from 0.25 wt.% to 0.42 wt.%, the morphology of grain changed from equiaxed shape to pan-cake shape and grain size also increased. The Charpy V notch (CVN impact energy of G11 and G12 steel at room temperature was 32 J and 4 J respectively and their fractographs revealed brittle rupture with cleavage facets for both the steels. However, the fractograph of G11 steel after tensile test exhibited ductile mode of fracture with conical equiaxed dimple while that of G12 steel containing 0.42 wt. % P exhibited transgranular cleavage fracture. Based on this study, G11 steel containing 0.25 wt. % P could be explored as a candidate material for weathering application purpose where the 20°C toughness requirement is 27 J as per CSN EN10025-2:2004 specification.

  5. Corrosion Resistance of High Performance Weathering Steel for Bridge Building Applications

    Institute of Scientific and Technical Information of China (English)

    CHENAi—hua; XUJian—qiu; LIRan; LIHua—long

    2012-01-01

    The mechanical properties, corrosion resistance and microstructures of high performance steel (HPS) was investigated by tensile testing machine, Charpy V-Notch (CVN) testing machine, cyclic immersion corrosion tester, XRD, optical microscopy (OM), scanning electron microscopy (SEM), and electron probe micro-analyzer (EPMA). The results showed that significant differences existed in the tensile strength, yield strength and impact toughness between HPS and PCS. After 72 h cyclic immersion accelerated corrosion test, the inner rust layer on HPS was com- posed of a-FeOOH phase and denser than that on PCS that was a mixture of a-FeOOH and Fe3 04. The rust formed on HPS provides better protection and HPS has lower corrosion rates than PCS. Copper and chromium in HPS en- rich in the rust layer and enhance the compactness of the rust layer. Based on the results of the accelerated corrosion tests and rust layer analysis, the roles of Cu and Cr against corrosion are discussed, providing HPS with chemical specification which has been industrially successful to produce weathering steel for bridge structure.

  6. Effect of twice quenching and tempering on the mechanical properties and microstructures of SCRAM steel for fusion application

    Energy Technology Data Exchange (ETDEWEB)

    Xiong Xuesong; Yang Feng; Zou Xingrong [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Suo Jinping, E-mail: jpsuo@yahoo.com.cn [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2012-11-15

    The effect of twice quenching and tempering on the mechanical properties and microstructures of SCRAM steel was investigated. The results from tensile tests showed that whether twice quenching and tempering processes(1253 K/0.5 h/W.C(water cool) + 1033 K/2 h/A.C(air cool) + 1233 K/0.5 h/W.C + 1033 K/2 h/A.C named after 2Q and 2TI, and 1253 K/0.5 h/W.C + 1033 K/2 h/A.C + 1233 K/0.5 h/W.C + 1013 K/2 h/A.C named after 2Q and 2TII)increased strength of steel or not depended largely on the second tempering temperature compared to quenching and tempering process(1253 K/0.5 h/W.C + 1033 K/2 h/A.C named after 1Q and 1T). Charpy V-notch impact tests indicated that twice quenching and tempering processes reduced the ductile brittle transition temperature (DBTT). Microstructure inspection revealed that the prior austenitic grain size and martensite lath width were refined after twice quenching and tempering treatments. Precipitate growth was inhibited by a slight decrease of the second tempering temperature from 1033 to 1013 K. The finer average size of precipitates is considered to be the main possible reason for the higher strength and lower DBTT of 2Q and 2TII compared with 2Q and 2TI.

  7. Results of crack-arrest tests on two irradiated high-copper welds

    Energy Technology Data Exchange (ETDEWEB)

    Iskander, S.K.; Corwin, W.R.; Nanstead, R.K. (Oak Ridge National Lab., TN (USA))

    1990-12-01

    The objective of this study was to determine the effect of neutron irradiation on the shift and shape of the lower-bound curve to crack-arrest data. Two submerged-arc welds with copper contents of 0.23 and 0.31 wt % were commercially fabricated in 220-mm-thick plate. Crack-arrest specimens fabricated from these welds were irradiated at a nominal temperature of 288{degree}C to an average fluence of 1.9 {times} 10{sup 19} neutrons/cm{sup 2} (>1 MeV). Evaluation of the results shows that the neutron-irradiation-induced crack-arrest toughness temperature shift is about the same as the Charpy V-notch impact temperature shift at the 41-J energy level. The shape of the lower-bound curves (for the range of test temperatures covered) did not seem to have been altered by irradiation compared to those of the ASME K{sub Ia} curve. 9 refs., 21 figs., 10 tabs.

  8. Analysis of the strengthening mechanisms in pipeline steels as a function of the hot rolling parameters

    Energy Technology Data Exchange (ETDEWEB)

    Carretero Olalla, V., E-mail: Victor.carretero@ugent.be [Ghent University, Department of Materials Science and Engineering, Technologiepark 903, Zwijnaarde, B-9052 Gent (Belgium); Bliznuk, V., E-mail: vitaliy.bliznuk@ugent.be [Ghent University, Department of Materials Science and Engineering, Technologiepark 903, Zwijnaarde, B-9052 Gent (Belgium); Sanchez, N., E-mail: nuria.sanchezmourino@arcelormittal.com [ArcelorMittal Global R and D Gent, OCAS NV Pres. J.F. Kennedylaan 3, BE-9060 Zelzate (Belgium); Thibaux, P., E-mail: philippe.thibaux@arcelormittal.com [ArcelorMittal Global R and D Gent, OCAS NV Pres. J.F. Kennedylaan 3, BE-9060 Zelzate (Belgium); Kestens, L.A.I., E-mail: leo.kestens@ugent.be [Ghent University, Department of Materials Science and Engineering, Technologiepark 903, Zwijnaarde, B-9052 Gent (Belgium); Delft University of Technology, Department of Materials Science and Engineering, Mekelweg 2, 2628 CD Delft (Netherlands); Petrov, R.H., E-mail: Roumen.Petrov@ugent.be [Ghent University, Department of Materials Science and Engineering, Technologiepark 903, Zwijnaarde, B-9052 Gent (Belgium); Delft University of Technology, Department of Materials Science and Engineering, Mekelweg 2, 2628 CD Delft (Netherlands)

    2014-05-01

    The yield strength of different pipeline steel grades, rolled under four different conditions, was correlated with calculated strengthening contributions. Slabs with the same composition were rolled under identical roughing conditions but varied finish rolling temperature (FRT). Two cooling routes, consisting of accelerated water cooling condition (ACC) followed by slow cooling in an oven to simulate coiling and air cooling were applied after the last rolling pass. The microstructures obtained after each thermo mechanical controlled process (TMCP) schedule, were characterized using Transmission Electron Microscopy (TEM), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Electron backscatter diffraction (EBSD). The mechanical properties of the plates were determined by means of tensile tests and Charpy V-notch impact test. It was confirmed that a combination of fast cooling rate and low finish rolling temperature produces higher strength than the slow cooling rate and high finish rolling temperature. Contributions to the strengthening arising from the various microstructural features like solid solution strengthening, grain size, dislocation density and precipitation hardening, were analyzed using Taylor, Hall–Petch and Ashby–Orowan approaches. The root of the sum of the squares method was applied to link the experimental with the model-predicted strength. It is believed that this approach provides a better understanding of the effect of TMCP parameters on the microstructure and strengthening mechanisms in pipeline steels.

  9. Further application of the cleavage fracture stress model for estimating the T0 of highly embrittled ferritic steels

    International Nuclear Information System (INIS)

    The semi-empirical cleavage fracture stress model (CFS), based on the microscopic cleavage fracture stress, sf, for estimating the ASTM E1921 reference temperature (T0) of ferritic steels from instrumented impact testing of unprecracked Charpy V-notch specimens is further confirmed by test results for additional steels, including steels highly embrittled by thermal aging or irradiation. In addition to the ferrite-pearlite, bainitic or tempered martensitic steels (which was examined earlier), acicular or polygonal ferrite, precipitation-strengthened or additional simulated heat affected zone steels are also evaluated. The upper limit for the applicability of the present CFS model seems to be T41J ∝160 to 170 C or T0 or TQcfs (T0 estimate from the present CFS model) ∝100 to 120 C. This is not a clear-cut boundary, but indicative of an area of caution where generation and evaluation of further data are required. However, the present work demonstrates the applicability of the present CFS model even to substantially embrittled steels. The earlier doubts expressed about TQcfs becoming unduly non-conservative for highly embrittled steels has not been fully substantiated and partly arises from the necessity of modifications in the T0 evaluation itself at high degrees of embrittlement suggested in the literature.

  10. Analysis of the strengthening mechanisms in pipeline steels as a function of the hot rolling parameters

    International Nuclear Information System (INIS)

    The yield strength of different pipeline steel grades, rolled under four different conditions, was correlated with calculated strengthening contributions. Slabs with the same composition were rolled under identical roughing conditions but varied finish rolling temperature (FRT). Two cooling routes, consisting of accelerated water cooling condition (ACC) followed by slow cooling in an oven to simulate coiling and air cooling were applied after the last rolling pass. The microstructures obtained after each thermo mechanical controlled process (TMCP) schedule, were characterized using Transmission Electron Microscopy (TEM), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Electron backscatter diffraction (EBSD). The mechanical properties of the plates were determined by means of tensile tests and Charpy V-notch impact test. It was confirmed that a combination of fast cooling rate and low finish rolling temperature produces higher strength than the slow cooling rate and high finish rolling temperature. Contributions to the strengthening arising from the various microstructural features like solid solution strengthening, grain size, dislocation density and precipitation hardening, were analyzed using Taylor, Hall–Petch and Ashby–Orowan approaches. The root of the sum of the squares method was applied to link the experimental with the model-predicted strength. It is believed that this approach provides a better understanding of the effect of TMCP parameters on the microstructure and strengthening mechanisms in pipeline steels

  11. Further application of the cleavage fracture stress model for estimating the T{sub 0} of highly embrittled ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Sreenivasan, P.R.

    2016-02-15

    The semi-empirical cleavage fracture stress model (CFS), based on the microscopic cleavage fracture stress, s{sub f}, for estimating the ASTM E1921 reference temperature (T{sub 0}) of ferritic steels from instrumented impact testing of unprecracked Charpy V-notch specimens is further confirmed by test results for additional steels, including steels highly embrittled by thermal aging or irradiation. In addition to the ferrite-pearlite, bainitic or tempered martensitic steels (which was examined earlier), acicular or polygonal ferrite, precipitation-strengthened or additional simulated heat affected zone steels are also evaluated. The upper limit for the applicability of the present CFS model seems to be T{sub 41J} ∝160 to 170 C or T{sub 0} or T{sub Qcfs} (T{sub 0} estimate from the present CFS model) ∝100 to 120 C. This is not a clear-cut boundary, but indicative of an area of caution where generation and evaluation of further data are required. However, the present work demonstrates the applicability of the present CFS model even to substantially embrittled steels. The earlier doubts expressed about T{sub Qcfs} becoming unduly non-conservative for highly embrittled steels has not been fully substantiated and partly arises from the necessity of modifications in the T{sub 0} evaluation itself at high degrees of embrittlement suggested in the literature.

  12. Application of the Master Curve approach for the irradiation embrittlement evaluation of pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Viehrig, H.W.; Boehmert, J. [Forschungszentrum Rossendorf e.V., Inst. fuer Sicherheitsforschung, Dresden (Germany)

    2003-09-01

    The master curve (MC) approach and the associated reference temperature, T{sub 0}, as defined in the test standard ASTM E1921, is rapidly moving from the research laboratory to application in integrity assessment of components and structures. T{sub 0} is the index temperature for the universal MC, which considers the toughness behaviour of a specific material. ''The Structural Integrity Assessment Procedures for European Industry'' (SINTAP) contain a MC extension for analysing the fracture behaviour of inhomogeneous ferritic steels. This paper presents the application of the MC approach to the T{sub 0} determination of different types of Russian WWER-type reactor pressure vessel (RPV) steels. In addition the SINTAP-MC approach was applied to determine an alternative reference temperature, T{sub R}. The influence of different microstructures and compositions within one type of RPV steel and the effect of irradiation with fast neutrons on T{sub 0} are experimentally evaluated. In general the MC based T{sub 0} is about 72 K below the Charpy V-notch transition temperature related to an impact energy of 48 J. The paper demonstrates the application of MC based T{sub 0} and T{sub R} as an alternative reference temperature for neutron embrittled RPV steels used in the RPV integrity assessment. (orig.)

  13. 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.

  14. The effect of reduced oxygen content powder on the impact toughness of 316 steel powder joined to 316 steel by low temperature HIP

    International Nuclear Information System (INIS)

    During the manufacture of the blanket modules, 316L steel powder is simultaneously consolidated and joined to tubes and blocks of 316L materials by Hot Isostatic Pressing (HIP). The high processing temperature can detrimentally increase the grain size of the water cooling tubes in the structure and the blocks reducing their strength. It is well known that surface oxides on the powder particles negatively influence the impact toughness of material and joints consolidated in this way. By increasing the consolidation temperature the metallurgical bonding is improved, due to a redistribution of oxygen within the oxide layer towards more discrete oxide particles. In order to get acceptable mechanical properties of materials produced at a low HIP temperature the oxygen content on the powder surfaces needs to be reduced. The aim of this new techniques to reduce the oxygen content of the metal powder. The influence on Charpy impact energy and tensile strength were demonstrated

  15. Single specimen fracture toughness determination procedure using instrumented impact test

    International Nuclear Information System (INIS)

    In the study a new single specimen test method and testing facility for evaluating dynamic fracture toughness has been developed. The method is based on the application of a new pendulum type instrumented impact tester equipped with and optical crack mouth opening displacement (COD) extensometer. The fracture toughness measurement technique uses the Double Displacement Ratio (DDR) method, which is based on the assumption that the specimen is deformed as two rigid arms that rotate around an apparent centre of rotation. This apparent moves as the crack grows, and the ratio of COD versus specimen displacement changes. As a consequence the onset ductile crack initiation can be detected on the load-displacement curve. Thus, an energy-based fracture toughness can be calculated. In addition the testing apparatus can use specimens with the Double ligament size as compared with the standard Charpy specimen which makes the impact testing more appropriate from the fracture mechanics point of view. The novel features of the testing facility and the feasibility of the new DDR method has been verified by performing an extensive experimental and analytical study. (99 refs., 91 figs., 27 tabs.)

  16. Irradiation, Annealing, and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels

    International Nuclear Information System (INIS)

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVs) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. Even though a postirradiation anneal may be deemed successful, a critical aspect of continued RPV operation is the rate of embrittlement upon reirradiation. There are insufficient data available to allow for verification of available models of reirradiation embrittlement or for the development of a reliable predictive methodology. This is especially true in the case of fracture toughness data. Under the U.S.-Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS), Working Group 3 on Radiation Embrittlement, Structural Integrity, and Life Extension of Reactor Vessels and Supports agreed to conduct a comparative study of annealing and reirradiation effects on RPV steels. The Working Group agreed that each side would irradiate, anneal, reirradiate (if feasible ), and test two materials of the other. Charpy V-notch (CVN) and tensile specimens were included. Oak Ridge National Laboratory (ORNL) conducted such a program (irradiation and annealing, including static fracture toughness) with two weld metals representative of VVER-440 and VVER-1000 RPVs, while the Russian Research Center-Kurchatov Institute (RRC-KI) conducted a program (irradiation, annealing, reirradiation, and reannealing) with Heavy-Section Steel Technology (HSST) Program Plate 02 and Heavy-Section Steel Irradiation (HSSI) Program Weld 73W. The results for each material from each laboratory are compared with those from the other laboratory. The ORNL experiments with the VVER welds included irradiation to about 1 x 1019 n/cm2 (>1 MeV), while the RRC-KI experiments with the U.S. materials included irradiations from about 2 to 18 x 1019 n/cm2 (>l MeV). In both cases, irradiations were conducted at ∼290 C and annealing treatments were conducted at ∼454 C. The ORNL and RRC

  17. Impact and hardness optimisation of composite materials inspired by the babassu nut (Orbignya speciosa).

    Science.gov (United States)

    Staufenberg, Gerrit; Graupner, Nina; Müssig, Jörg

    2015-08-20

    The babassu nut is the fruit of the babassu palm Orbignya speciosa. The combination of hardness and impact strength is difficult to acquire for artificial materials, making the babassu nut a promising source for biomimetic inspiration. Unnotched Charpy impact tests, Shore D hardness tests and scanning electron microscopy were used for mechanical and microscopical analysis of the pericarp. Four major principles were found for a biomimetic approach: a hard core ((1); endocarp) is embedded in a soft outer layer of high impact strength ((2); epicarp) and is reinforced with fibres of variable fineness (3), some of which are oriented radial to the core (4). Biomimetic fibre-reinforced composites were produced using abstracted mechanisms of the babassu nut based on regenerated cellulose fibres (lyocell, L) with two different fineness values as reinforcement embedded in a polylactide (PLA) core matrix and polypropylene (PP) based outer layers. The biomimetic fibre composite reaches a significantly higher impact strength that is 1.6 times higher than the reference sample produced from a PLA/PP/L-blend. At the same time the hardness is slightly increased compared to PP/L.

  18. Investigations on the impact strength of constructional high-strength Weldox steel at lowered temperature

    Directory of Open Access Journals (Sweden)

    W. Ozgowicz

    2008-08-01

    Full Text Available Purpose: The paper presents the results of investigations concerning the impact strength of thick steel plates at lowered temperature obtained by industrial smelting of micro-alloyed steel of the type S1100QL (Weldox 1100 and S1300QL (Weldox 1300 with a yield strength of 1100-1300 MPa.Design/methodology/approach: The main methods used for these researches were the impact test Charpy V at lower temperatures, and metallographic observations. The tested samples at lower temperature have also been analyzed fractographically.Findings: The influence of the chemical composition and technology of production on the structure and mechanical properties of the investigated kinds of steels have been determined, as well as their ductility temperature of transition into the brittle state.Research limitations/implications: A large dispersion of intermetallic precipitated phases restricted considerably the possibility of their metallographic identification. This latter one will be done in the next stage of basic investigations.Practical implications: A wide range of practical applications of Weldox 1100 and Weldox 1300 sheet plates is warranted by both their high impact strength, especially at lower temperatures, and lower ductility transition temperature.Originality/value: It has been found that the degree of refinement of the martensitic structure and dispersion of secondary precipitations, mainly carbides and niobium nitrocarbides affect considerably the change of the impact strength within the investigated range of temperature from ambient temperature to minus 150°C.

  19. Irradiation and annealing behavior of 15Kh2MFA reactor pressure vessel steel

    International Nuclear Information System (INIS)

    This work deals with the mechanical properties of RPV steels used WWER-440. The materials under investigation were a forging (base metal 15Kh2MFA) and the corresponding weld. Charpy V-notch specimens and tensile test specimens were irradiated in the WWER-2 Rheinsberg at about 270 C up to the two neutron fluence levels of 4 x 1018 and 5 x 1019 n/cm2 (E>1MeV). Post-irradiation annealing heat treatments were performed, among others a 475 C/152 h treatment of technical interest. (orig.)

  20. Weldability of thermally grain-refined Fe-12Ni-0.25Ti for cryogenic structural applications

    International Nuclear Information System (INIS)

    The weldability of a research alloy designed for structural use in liquid helium temperature, cryogenic environments was investigated. Plates of iron-12 weight percent nickel-0.25 weight percent titanium were grain refined by the four-step, grain refining thermal treatment developed for this alloy and welded with Inconel Number 92 weld wire using the Gas Metal Arc (GMA) welding process with argon-15% helium gas shielding. Both a single pass and a double-sided, 2 pass electron beam (EB) weld were also made without filler metal addition. Weldments were radiographed and sectioned and the charpy V-notch specimens removed were tested at liquid nitrogen and helium temperatures

  1. Aplicación del ensayo miniatura de embutido para la evaluación de la tenacidad a temperaturas criogénicas de aceros inoxidables austeníticos envejecidos isotérmicamente

    OpenAIRE

    Saucedo-Muñoz, M. L.; Komazaki, S. I.; T. Hashida; Shoji, T; López-Hirata, V. M.

    2003-01-01

    Two types of austenitic stainless steels JJl and JNl were isothermally aged at temperatures from 873 to 1173 K for 10 to 1000 min in order to study the microstructural evolution and its effect on fracture toughness at cryogenic temperatures. The Charpy V-Notch (CVN) and Small-Punch (SP)Testing methods were conducted at 77 K to evaluate the toughness of both solution treated and aged specimens. The fracture energy at 77 K determined for both methods showed a significant decrease with aging tim...

  2. A study of "475°C embrittlement" in Fe-20Cr and Fe-20Cr-X (X=Ni, Cu, Mn) alloys

    OpenAIRE

    Huyan, Fei

    2012-01-01

    The “475°C embrittlement” occurring in ferritic and duplex stainless steel is considered to be detrimental and it limits the application of ferritic and duplex stainless steel at elevated temperatures, i.e., above about 300°C . In this study, the effect from alloying elements Ni, Cu and Mn on 475°C embrittlement was examined based on microhardness measurement and Charpy V-notch tests as well as atom probe tomography (APT). It was found that, after aging for 10h, 3% Ni accelerates the ferrite ...

  3. Assessment of high-strength stainless steel weldments for fusion energy applications

    International Nuclear Information System (INIS)

    Primary design considerations for the Compact Ignition Tokomak fusion reactor magnet cases are yield strength and toughness in the temperature range from liquid nitrogen to room temperature (77 to 300K). Type 21-6-9 stainless steel, also known as Nitronic 40, is the proposed alloy for this application. This study documented the mechanical properties, including tensile yield strength and Charpy V-notch impact toughness, at 77K and room temperature, of weldments made using seven different filler metals. Six welds were made with filler metal added as cold filler wire using the argon-shielded gas tungsten arc welding process. Filler metals included Nitronic 35W and 40W, 21-6-9, ERNiCr-3 (Inconel 82), ERNiCrMo-3 (Inconel 625), and Inconel 625 PLUS. All welds were prepared with a double-groove butt-weld geometry. At room temperature, all of the filler metals had yield strengths which exceeded the base metal. However, at 77K only the Nitronics and the 21-6-9 filler metals exceeded the base metals, and the Inconel filler metals were significantly weaker. The impact properties of the weld metals were very good at room temperature, with the exception of Inconel 625. At 77K, impact toughness was greatly reduced for all of the filler metals with the exception of Inconel 82. This alloy had excellent toughness at both temperatures. The severe drop in the impact toughness of the Nitronic and 21-6-9 filler metals was attributed to the amount of ferrite present in these welds. At 77K, fracture occurred by a cleavage mechanism in the ferrite regions which allowed the crack to grow readily. The fully austenitic Inconel 82 material fractured by a microvoid coalescence mode at either test temperature. These results indicate that the Inconel 82 filler metal is the preferred material for welding 21-6-o stainless steel for this application

  4. Heat-Resistant Ferritic-Martensitic Steel RUSFER-EK-181 (Fe-12Cr-2W-V-Ta-B) for Fusion Power Reactor

    International Nuclear Information System (INIS)

    Full text: The study of initial (unirradiated) functional properties of Russian RAFMS RUSFER-EK-181 (Fe-12Cr-2W-V-Ta-B) as advanced heat-and radiation-resistant structural material for fusion power reactors has been continued. RUSFER-EK-181 steel is related to precipitation hardening (nanostructured) materials type. The regularities of low temperature brittle fracture (crack growth resistance) of the steel at static and dynamic concentrated loads depending on the sizes of Charpy V-Noch (CVN) specimens, type of stress concentrators (V-notches or a fatigue crack) were investigated in the temperature range from -196 deg. C to +100 deg. C. Fracture toughness tests estimating KIC and JIC (static concentrated bending) were conducted. The ductile-to-brittle transition temperatures (DBTT) were determined in the range from -85 deg. C to +35 deg. C depending on the type of CVN-specimens and stress states (fatigue crack, central and side V-notches). The work of low temperature fracture of the steel depends on the type of the stress concentrators and specimen sizes and is governed by the elastic energy store and the conditions of plastic deformation in the near-surface layers of the specimens regulated by side notches. The marked level of permanent deformation and impact toughness (not less than 3 - 5 J/cm2) was observed at low temperatures (lower than DBTT). Short-term (yield strength, ultimate strength, elongation to rupture) and long-term (creep, diagram 'stress vs time to rupture') properties, temperature conductivity, thermal conductivity and linear expansion of the steel were investigated in the temperature range to 750oC. Diffusion characteristics of self-point defects (vacancies and interstitial atoms) in iron crystal with dislocations of different types were calculated by the methods of multiscale modeling in the temperature range from room temperature to 1000K. Nuclear transmutation changes of the chemical composition and the structure and phase state (Schaeffler

  5. The cryogenic bonding evaluation at the metallic-composite interface of a composite overwrapped pressure vessel with additional impact investigation

    Science.gov (United States)

    Clark, Eric A.

    A bonding evaluation that investigated the cryogenic tensile strength of several different adhesives/resins was performed. The test materials consisted of 606 aluminum test pieces adhered to a wet-wound graphite laminate in order to simulate the bond created at the liner-composite interface of an aluminum-lined composite overwrapped pressure vessel. It was found that for cryogenic applications, a flexible, low modulus resin system must be used. Additionally, the samples prepared with a thin layer of cured resin -- or prebond -- performed significantly better than those without. It was found that it is critical that the prebond surface must have sufficient surface roughness prior to the bonding application. Also, the aluminum test pieces that were prepared using a surface etchant slightly outperformed those that were prepared with a grit blast surface finish and performed significantly better than those that had been scored using sand paper to achieve the desired surface finish. An additional impact investigation studied the post impact tensile strength of composite rings in a cryogenic environment. The composite rings were filament wound with several combinations of graphite and aramid fibers and were prepared with different resin systems. The rings were subjected to varying levels of Charpy impact damage and then pulled to failure in tension. It was found that the addition of elastic aramid fibers with the carbon fibers mitigates the overall impact damage and drastically improves the post-impact strength of the structure in a cryogenic environment.

  6. Effect of direct quenching on the microstructure and mechanical properties of the lean-chemistry HSLA-100 steel plates

    International Nuclear Information System (INIS)

    Highlights: → Direct-quenched and tempered (DQT) steels gives better mechanical properties. → Fine Cu and Nb (C, N) precipitates enhance matrix strengthening and tempering resistance. → Boron promotes hardenability, but low temperature Charpy impact toughness gets affected. → Mechanical properties equivalent to HSLA-100 steel is achieved by directly quenched leaner chemistry alloys. - Abstract: The influence of direct quenching on structure-property behavior of lean chemistry HSLA-100 steels was studied. Two laboratory heats, one containing Cu and Nb (C:0.052, Mn:0.99, Cu:1.08, Nb:0.043, Cr:0.57, Ni:1.76, Mo:0.55 pct) and the other containing Cu, Nb and B (C:0.04, Mn:1.02, Cu:1.06, Nb:0.036, Cr:0.87, Ni:1.32, Mo:0.41, B:0.002 percent) were hot-rolled into 25 and 12.5 mm thick plates by varying finish-rolling temperatures. The plates were heat-treated by conventional reheat quenching and tempering (RQT), as well as by direct quenching and tempering (DQT) techniques. In general, direct-quench and tempered plates of Nb-Cu heat exhibited good strength (yield strength ∼ 900 MPa) and low-temperature impact toughness (average: 74 J at -85 deg. C); the Charpy V-notch impact energies were marginally lower than conventional HSLA-100 steel. In Nb-Cu-B heat, impact toughness at low-temperature was inferior owing to boron segregation at grain boundaries. Transmission electron microscopy (TEM) and scanning auger microprobe (SAM) analysis confirmed existence of borocarbides at grain boundaries in this steel. In general, for both the steels, the mechanical properties of the direct-quench and tempered plates were found to be superior to reheat quench and tempered plates. A detailed transmission electron microscopy study revealed presence of fine Cu and Nb (C, N) precipitates in these steels. It was also observed that smaller martensite inter-lath spacing, finer grains and precipitates in direct-quench and tempered plates compared to the reheat quench and tempered plates

  7. Effect of direct quenching on the microstructure and mechanical properties of the lean-chemistry HSLA-100 steel plates

    Energy Technology Data Exchange (ETDEWEB)

    Dhua, S.K., E-mail: skdhua@yahoo.com [R and D Centre for Iron and Steel, Steel Authority of India Limited, Doranda, Ranchi 834002 (India); Sen, S.K., E-mail: sksen@sail-rdcis.com [R and D Centre for Iron and Steel, Steel Authority of India Limited, Doranda, Ranchi 834002 (India)

    2011-08-15

    Highlights: {yields} Direct-quenched and tempered (DQT) steels gives better mechanical properties. {yields} Fine Cu and Nb (C, N) precipitates enhance matrix strengthening and tempering resistance. {yields} Boron promotes hardenability, but low temperature Charpy impact toughness gets affected. {yields} Mechanical properties equivalent to HSLA-100 steel is achieved by directly quenched leaner chemistry alloys. - Abstract: The influence of direct quenching on structure-property behavior of lean chemistry HSLA-100 steels was studied. Two laboratory heats, one containing Cu and Nb (C:0.052, Mn:0.99, Cu:1.08, Nb:0.043, Cr:0.57, Ni:1.76, Mo:0.55 pct) and the other containing Cu, Nb and B (C:0.04, Mn:1.02, Cu:1.06, Nb:0.036, Cr:0.87, Ni:1.32, Mo:0.41, B:0.002 percent) were hot-rolled into 25 and 12.5 mm thick plates by varying finish-rolling temperatures. The plates were heat-treated by conventional reheat quenching and tempering (RQT), as well as by direct quenching and tempering (DQT) techniques. In general, direct-quench and tempered plates of Nb-Cu heat exhibited good strength (yield strength {approx} 900 MPa) and low-temperature impact toughness (average: 74 J at -85 deg. C); the Charpy V-notch impact energies were marginally lower than conventional HSLA-100 steel. In Nb-Cu-B heat, impact toughness at low-temperature was inferior owing to boron segregation at grain boundaries. Transmission electron microscopy (TEM) and scanning auger microprobe (SAM) analysis confirmed existence of borocarbides at grain boundaries in this steel. In general, for both the steels, the mechanical properties of the direct-quench and tempered plates were found to be superior to reheat quench and tempered plates. A detailed transmission electron microscopy study revealed presence of fine Cu and Nb (C, N) precipitates in these steels. It was also observed that smaller martensite inter-lath spacing, finer grains and precipitates in direct-quench and tempered plates compared to the reheat

  8. Extended analysis of WWER-1000 Charpy test data

    International Nuclear Information System (INIS)

    The aim of this work is to study the embrittlement rate of WWER-1000 RPV weld metal with high Ni content and to determine influence of neutron irradiation on partial energies of ductile crack initiation, stable and unstable crack propagation and post crack arrest. (author)

  9. An Investigation on the Wear Resistance and Fatigue Behaviour of Ti-6Al-4V Notched Members Coated with Hydroxyapatite Coatings

    Directory of Open Access Journals (Sweden)

    Reza H Oskouei

    2016-02-01

    Full Text Available In this study, surface properties of Ti-6Al-4V alloy coated with hydroxyapatite coatings were investigated. Wear resistance and fatigue behaviour of samples with coating thicknesses of 10 and 50 µm as well as uncoated samples were examined. Wear experiments demonstrated that the friction factor of the uncoated titanium decreased from 0.31 to 0.06, through a fluctuating trend, after 50 cycles of wear tests. However, the friction factor of both the coated samples (10 and 50 µm gradually decreased from 0.20 to 0.12 after 50 cycles. At the end of the 50th cycle, the penetration depth of the 10 and 50 µm coated samples were 7.69 and 6.06 µm, respectively. Fatigue tests showed that hydroxyapatite coatings could improve fatigue life of a notched Ti-6Al-4V member in both low and high cycle fatigue zones. It was understood, from fractography of the fracture surfaces, that the fatigue zone of the uncoated specimens was generally smaller in comparison with that of the coated specimens. No significant difference was observed between the fatigue life of coated specimens with 10 and 50 µm thicknesses.

  10. Characteristics of the IAEA correlation monitor material for surveillance programmes

    International Nuclear Information System (INIS)

    Within the IAEA Coordinated Research Programme on optimizing of reactor pressure vessel surveillance programmes and their analysis, phase 3, a specially tailored 'radiation sensitive' correlation monitor material has been fabricated. This material will serve as a reference to the IAEA programme for future vessel surveillance programmes throughout the world. An extensive evaluation of the correlation monitor material in the as-received condition has been carried out in Finland and the results are presented here. The mechanical properties measured at different temperatures include Charpy V notch and instrumented precracked Charpy data, and elastic-plastic fracture toughness (J). The specimen size and geometry have been varied in the tests. Correlation between different fracture properties are evaluated and discussed

  11. Permanent effect of a cryogenic spill on fracture properties of structural steels

    Science.gov (United States)

    Keseler, H.; Westermann, I.; Kandukuri, S. Y.; Nøkleby, J. O.; Holmedal, B.

    2015-12-01

    Fracture analysis of a standard construction steel platform deck, which had been exposed to a liquid nitrogen spill, showed that the brittle fracture started at a flaw in the weld as a consequence of low-temperature embrittlement and thermal stresses experienced by the material. In the present study, the permanent effect of a cryogenic spill on the fracture properties of carbon steels has been investigated. Charpy V-notch impact testing was carried out at 0 °C using specimens, from the platform deck material. The average impact energy appeared to be below requirements only for transverse specimens. No pre-existing damage was found when examining the fracture surfaces and cross sections in the scanning electron microscope. Specimens of the platform deck material and a DOMEX S355 MCD carbon steel were tensile tested immersed in liquid nitrogen. Both steels showed a considerable increase in yield- and fracture strength and a large increase in the Lüders strain compared to the room temperature behavior. A cryogenic spill was simulated by applying a constant tensile force to the specimens for 10 min, at -196 C. Subsequent tensile tests at room temperature showed no significant influence on the stress-strain curve of the specimens. A small amount of microcracks were found after holding a DOMEX S355 MCD specimen at a constant force below the yield point. In a platform deck material tensile tested to fracture in liquid nitrogen, cracks associated with elongated MnS inclusions were found through the whole test region. These cracks probably formed as a result of the inclusions having a higher thermal contraction rate than the steel, causing decohesion at the inclusion-matrix interface on cooling. Simultaneous deformation may have caused formation of cracks. Both the microcracks and sulphide related damage may give permanently reduced impact energy after a cryogenic exposure.

  12. Evaluation of weldments in Type 21-6-9 stainless steel for Compact Ignition Tokamak structural applications: Phase 1

    International Nuclear Information System (INIS)

    Primary design considerations for the Compact Ignition Tokamak toroidal field-coil cases are yield strength and toughness in the temperature range from 77 to 300 K. Type 21-6-9 stainless steel, also still known by its original Armco Steel Company trade name Nitronic 40, is the proposed alloy for this application. It has high yield strength and usually adequate base metal toughness, but weldments in thick sections have not been adequately characterized in terms of mechanical properties or hot-cracking propensity. In this study, weldability of the alloy in heavy sections and the mechanical properties of the resultant welds were investigated including tensile yield strength and Charpy V-notch toughness at 77 K and room temperature. Weldments were made in four different base metals using seven different filler metals. None of the weldments showed any indication of hot-cracking problems. All base metals, including weldment heat-affected zones, were found to have adequate strength and impact toughness at both test temperatures. Weld metals, on the other hand, except ERNiCr-3 and ENiCrFe-3 had impact toughnesses of less than 67 J at 77 K. Inconel 82 had an average weld metal impact toughness of over 135 J at 77 K, and although its strength at 77 K is less than that of type 21-6-9 base metal, at this point it is considered to be the first-choice filler metal. Phase 2 of this program will concentrate on composition refinement and process/procedure optimization for the generic ERNiCr-3 composition and will generate a design data base for base and weld metal, including tensile, fracture toughness, and crack growth rate data

  13. Enhancement of Impact Toughness by Delamination Fracture in a Low-Alloy High-Strength Steel with Al Alloying

    Science.gov (United States)

    Sun, Junjie; Jiang, Tao; Liu, Hongji; Guo, Shengwu; Liu, Yongning

    2016-09-01

    The effect of delamination toughening of martensitic steel was investigated both at room and low temperatures [253 K and 233 K (-20 °C and -40 °C)]. Two low-alloy martensitic steels with and without Al alloying were both prepared. Layered structure with white band and black matrix was observed in Al alloyed steel, while a homogeneous microstructure was displayed in the steel without Al. Both steels achieved high strength (tensile strength over 1600 MPa) and good ductility (elongation over 11 pct), but they displayed stark contrasts on impact fracture mode and Charpy impact energy. Delamination fracture occurred in Al alloyed steel and the impact energies were significantly increased both at room temperature (from 75 to 138 J, i.e., nearly improved up to 2 times) and low temperatures [from 47.9 to 71.3 J at 233 K (-40 °C)] compared with the one without Al. Alloying with Al promotes the segregation of Cr, Mn, Si and C elements to form a network structure, which is martensite with higher carbon content and higher hardness than that of the matrix. And this network structure evolved into a band structure during the hot rolling process. The difference of yield stress between the band structure and the matrix gives rise to a delamination fracture during the impact test, which increases the toughness greatly.

  14. EFFECTS OF TEMPERING TEMPERATURE ON THE IMPACT TOUGHNESS OF STEEL 42CrMo%回火温度对42CrMo钢冲击韧性的影响

    Institute of Scientific and Technical Information of China (English)

    陈俊丹; 莫文林; 王培; 陆善平

    2012-01-01

    以核电站环形起重机用42CrMo耐热钢为研究对象,分析了显微组织中碳化物形貌和分布随回火温度的变化及其对冲击韧性的影响.结果表明,42CrMo钢经水淬后在500 650℃区间回火,显微组织均为回火索氏体.随回火温度上升,12℃冲击功先增加后减小;经500和530℃回火后,片状碳化物不均匀分布于原马氏体板条界上,冲击功分别为26和44 J;600℃回火后碳化物呈颗粒状弥散分布,冲击功达到峰值104 J;600℃以上回火,颗粒状碳化物明显粗化,冲击功下降.碳化物的形貌和分布是影响42CrMo钢冲击性能的关键因素.%42CrMo heat-resistant steel is a kind of structural steel, which is widely used in structural components such as crane weight-on-wheel, automobile crank shaft, locomotive gear hub and so on, for its good hardening ability, high temperature strength, good creep resistance, and little quenching deformation. However, in industry application, mismatching between the strength and the toughness always occurs for 42CrMo structure components. In order to solve the problem that the strength does not match the toughness in the manufacturing process for the polar crane for the nuclear power station, the effect of tempering temperature on the morphology and distribution of carbides and the impact toughness has been investigated for steel 42CrMo in this study. The experimental results indicated that the microstructure of the quenched steel 42CrMo after 500-650 ℃ tempering was characterized by tempering sorbite. As the tempering temperature increased, the Charpy absorbed energy at -12 ℃ initially increased and then decreased. The flake carbides after 500 and 530 ℃ tempering are not evenly distributed on the original martensite boundaries, the Charpy absorbed energy are 26 and 44 J, respectively. While the granular carbides are evenly distributed in the microstructure after 600 ℃ tempering, the Charpy absorbed energy reaches a maximum

  15. Tensile and impact testing of an HFBR [High Flux Beam Reactor] control rod follower

    International Nuclear Information System (INIS)

    The Materials Technology Group of the Department of Nuclear Energy (DNE) at Brookhaven National Laboratory (BNL) undertook a program to machine and test specimens from a control rod follower from the High Flux Beam Reactor (HFBR). Tensile and Charpy impact specimens were machined and tested from non-irradiated aluminum alloys in addition to irradiated 6061-T6 from the HFBR. The tensile test results on irradiated material showed a two-fold increase in tensile strength to a maximum of 100.6 ksi. The impact resistance of the irradiated material showed a six-fold decrease in values (3 in-lb average) compared to similar non-irradiated material. Fracture toughness (KI) specimens were tested on an unirradiated compositionally and dimensionally similar (to HFBR follower) 6061 T-6 material with Kmax values of 24.8 ± 1.0 Ksi√in (average) being obtained. The report concludes that the specimens produced during the program yielded reproducible and believable results and that proper quality assurance was provided throughout the program. 9 figs., 6 tabs

  16. Effect of double quenching and tempering heat treatment on the microstructure and mechanical properties of a novel 5Cr steel processed by electro-slag casting

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jian, E-mail: healygo@163.com; Yu, Hao, E-mail: yuhao@ustb.edu.cn; Zhou, Tao, E-mail: zhoutao130984@163.com; Song, Chenghao, E-mail: songchenghao28@126.com; Zhang, Kai, E-mail: zhangkai8901@126.com

    2014-12-01

    The effect of double quenching and tempering (DQT) treatment as well as conventional high temperature quenching and tempering (CQT) treatment on the microstructures and mechanical properties of low carbon 5Cr martensitic as cast steel produced by electroslag casting was investigated. The microstructure changes were characterized by optical microscope (OM), scanning electron microscope (SEM), electron back scatter diffraction (EBSD) and transmission electron microscopy (TEM). The characteristics of carbides precipitated during tempering were analyzed on both carbon extraction replica and thin foil samples by TEM. The mechanical performance was evaluated by Vickers hardness test, tensile test, and Charpy V-notch impact test at ambient temperature. The results of microstructure study indicated that DQT treatment led to a finer microstructure than that of CQT. The carbides of the tempered samples were identified as M{sub 7}C{sub 3}. The carbides along the prior austenite grain boundaries nucleated directly while those within the laths should be transformed from cementite which formed at the early tempering stage. Compared with CQT condition, yield strength slightly increased after DQT treatment, and impact toughness improved a lot. The strengthening mechanisms were analyzed and it was found that grain refining and precipitation strengthening were mainly responsible for the increase of strength. The superior toughness of DQT condition was attributed to the finer microstructure resulting in more frequent deflections of the cleavage crack and the smaller size of carbides along the prior austenite boundaries. EBSD analysis showed that both martensitic block and packet of low carbon 5Cr tempered martensitic steel could hinder crack propagation, while the latter was more effective.

  17. Effect of double quenching and tempering heat treatment on the microstructure and mechanical properties of a novel 5Cr steel processed by electro-slag casting

    International Nuclear Information System (INIS)

    The effect of double quenching and tempering (DQT) treatment as well as conventional high temperature quenching and tempering (CQT) treatment on the microstructures and mechanical properties of low carbon 5Cr martensitic as cast steel produced by electroslag casting was investigated. The microstructure changes were characterized by optical microscope (OM), scanning electron microscope (SEM), electron back scatter diffraction (EBSD) and transmission electron microscopy (TEM). The characteristics of carbides precipitated during tempering were analyzed on both carbon extraction replica and thin foil samples by TEM. The mechanical performance was evaluated by Vickers hardness test, tensile test, and Charpy V-notch impact test at ambient temperature. The results of microstructure study indicated that DQT treatment led to a finer microstructure than that of CQT. The carbides of the tempered samples were identified as M7C3. The carbides along the prior austenite grain boundaries nucleated directly while those within the laths should be transformed from cementite which formed at the early tempering stage. Compared with CQT condition, yield strength slightly increased after DQT treatment, and impact toughness improved a lot. The strengthening mechanisms were analyzed and it was found that grain refining and precipitation strengthening were mainly responsible for the increase of strength. The superior toughness of DQT condition was attributed to the finer microstructure resulting in more frequent deflections of the cleavage crack and the smaller size of carbides along the prior austenite boundaries. EBSD analysis showed that both martensitic block and packet of low carbon 5Cr tempered martensitic steel could hinder crack propagation, while the latter was more effective

  18. High Manganese and Aluminum Steels for the Military and Transportation Industry

    Science.gov (United States)

    Bartlett, Laura; Van Aken, David

    2014-09-01

    Lightweight advanced high strength steels (AHSS) with aluminum contents between 4 and 12 weight percent have been the subject of intense interest in the last decade because of an excellent combination of high strain rate toughness coupled with up to a 17% reduction in density. Fully austenitic cast steels with a nominal composition of Fe-30%Mn-9%Al-0.9%C are almost 15% less dense than quenched and tempered Cr-Mo steels (SAE 4130) with equivalent strengths and dynamic fracture toughness. This article serves as a review of the tensile and high-strain-rate fracture properties associated mainly with silicon additions to this base composition. In the solution-treated condition, cast steels have high work-hardening rates with elongations up to 64%, room-temperature Charpy V-notch (CVN) impact energies up to 200 J, and dynamic fracture toughness over 700 kJ/m2. Silicon additions in the range of 0.59-1.56% Si have no significant effect on the mechanical properties of solution-treated steels but increased the tensile strength and hardness during aging. For steels aged at 530°C to an average hardness of 310 Brinell hardness number, HBW, increasing the amount of silicon from 1.07% to 1.56% decreased the room temperature CVN breaking energy from 92 J to 68 J and the dynamic fracture toughness from 376 kJ/m2 to 265 kJ/m2. Notch toughness is a strong function of phosphorus content, decreasing the solution-treated CVN impact toughness from 200 J in a 0.006% P steel to 28 J in a 0.07% P steel. For age-hardened steels with 1% Si, increasing levels of phosphorus from 0.001% to 0.043% decreased the dynamic fracture toughness from 376 kJ/m2 to 100 kJ/m2.

  19. Development of nickel-free austenitic stainless steels for ambient and cryogenic applications

    Energy Technology Data Exchange (ETDEWEB)

    Haddick, G.T.; Thompson, L.D.; Parker, E.R.; Zackay, V.F.

    1978-02-01

    A series of alloys have been developed as possible replacements for some austenitic stainless steels. These alloys utilized a Mn substitution for Ni and a reduced Cr concentration from the 18% ordinarily found in the AISI 300 series stainless steels to a concentration of 13%. The base system studied was an alloy containing Fe-16%Mn-13%Cr while other elements added included small additions of N, Si and Mo. A range of microstructures was produced from the alloying additions. The base composition had a triplex (fcc, hcp, bcc) structure while the most highly modified compositions were fully austenitic. Mechanical testing included tensile testing and Charpy V-notch testing conducted at various temperatures between -196/sup 0/C to 23/sup 0/C. Excellent combinations of strength and ductility were obtained (40--65 ksi yield strength, 100--125 ksi ultimate strength, 45--75% elongation and 60--80% reduction of area) at room temperature. Upper shelf energies in Charpy V-notch testing were as high as 185 ft-lbs with a ductile-brittle transition temperature (DBTT) of -160/sup 0/C. Analysis of fracture surfaces determined that alloys without interstitials had no transition in the mode of failure between room temperature and liquid nitrogen temperature. Results of an ASTM sensitization corrosion test, where the experimental alloys were compared to 347 stainless steel, indicated that the alloys were not susceptible to intergranular attack.

  20. Enhanced Thermal Performance and Impact Strength of UHMWPE/Recycled-PA6 Blends Synthesized via a Melting Extrusion Route

    Directory of Open Access Journals (Sweden)

    Xiuying Yang

    2016-01-01

    Full Text Available The blends of ultra-high molecular weight polyethylene (UHMWPE and recycled-polyamide 6 (R-PA6 were prepared via a melting extrusion route using high-density polyethylene-graft-maleic anhydride (HDPE-g-MAH as the compatibilizer. The morphologies and distributions of the chemical components of the blends were characterized by scanning electron microscopy and synchrotron Fourier transform infrared microspectroscopy. The effects of R-PA6 content on the Vicat softening temperature (VST, heat distortion temperature (HDT, and impact strength of the blends were studied. Remarkably, in comparison with those of UHMWPE, the VST and HDT of UHMWPE/R-PA6 blends with 44 wt% R-PA6 were increased to 165.1 and 98.4°C, respectively, and the Charpy impact strength and Izod impact strength of the blends were enhanced to 33.9 and 16.2 kJ/m2, respectively. In addition, it was found that the blending system containing 44 wt% R-PA6 and 48 wt% UHMWPE exhibited the best compatibility when it was prepared using 8 wt% HDPE-g-MAH. The distribution of the phases of UHMWPE and R-PA6 was uniform, and no obvious phase separation was observed in the blends.

  1. Influence of Heat Input on Martensite Formation and Impact Property of Ferritic-Austenitic Dissimilar Weld Metals

    Institute of Scientific and Technical Information of China (English)

    M. Mukherjee; T.K. Pal

    2012-01-01

    The effect of heat input on martensite formation and impact properties of gas metal arc welded modified ferritic stainless steel (409M) sheets (as received) with thickness of 4 mm was described in detail in this work. The welded joints were prepared under three heat input conditions, i.e. 0.4, 0.5 and 0.6 kJ/mm using two different austenitic filler wires (308L and 316L) and shielding gas composition of Ar + 5% CO2. The welded joints were evaluated by microstructure and charpy impact toughness. The dependence of weld metal microstructure on heat input and filler wires were determined by dilution calculation, Creq/Nieq ratio, stacking fault energy (SFE), optical microscopy (OM) and transmission electron microscopy (TEM). It was observed that the microstructure as well as impact property of weld metal was significantly affected by the heat input and filler wire. Weld metals prepared by high heat input exhibited higher amount of martensite laths and toughness compared with those prepared by medium and low heat inputs, which was true for both the filler wires. Furthermore, 308L weld metals in general provided higher amount of martensite laths and toughness than 316L weld metals.

  2. The impact and hot tensile properties of 9Cr1Mo steel in various heat treatment conditions

    International Nuclear Information System (INIS)

    The impact and elevated temperature tensile properties of 9Cr1Mo in several heat treatment conditions have been studied to test the tolerance of the steel to departures from the material specification for AGR or fast reactor applications. The properties were found not to be sensitive to grain size or to the presence of grain boundary delta ferrite (<5%) which can arise in weld heat affected zones. Prior creep resulted in some loss of tensile strength but no loss of ductility was measured even though secondary precipitation had begun to develop under the conditions of the prior creep test. The dominant variable governing both tensile and impact properties was the state of temper and an empirical relationship was found between the tensile properties and hardness: the latter also being predictable by a Holloman-Jaffe form of expression. However, the Charpy impact properties of specimens aged near the service temperature (at 550 deg. C) were severely reduced by a mode of prior austenite grain boundary embrittlement manifested as severe intercrystalline failure. The embrittlement is of a type consistent with decohesion arising simply from equilibrium segregation (ie temper embrittlement). While the latter appears to make a significant contribution, interface decohesion is believed also to depend on concentration changes associated with carbide growth. (author)

  3. Irradiation effects on fracture toughness of two high-copper submerged-arc welds, HSSI series 5. Volume 2, Appendices E and F

    Energy Technology Data Exchange (ETDEWEB)

    Nanstad, R.K.; Haggag, F.M.; McCabe, D.E.; Iskander, S.K.; Bowman, K.O. [Oak Ridge National Lab., TN (United States); Menke, B.H. [Materials Engineering Associates, Inc., Lanham, MD (United States)

    1992-10-01

    The Fifth Irradiation Series in the Heavy-Section Steel irradiation (HSSI) Program was aimed at obtaining a statistically significant fracture toughness data base on two weldments with high-copper contents to determine the shift and shape of the K{sub lc} curve as a consequence of irradiation. The program included irradiated Charpy V-notch impact, tensile, and drop-weight specimens in addition to compact fracture toughness specimens. Compact specimens with thicknesses of 25.4, 50.8, and 101.6 mm [1T C(T), 2T C(T), and 4T C(T), respectively] were irradiated. Additionally, unirradiated 6T C(T) and 8T C(T) specimens with the same K{sub lc} measuring capacity as the irradiated specimens were tested. The materials for this irradiation series were two weldments fabricated from special heats of weld wire with copper added to the melt. One lot of Linde 0124 flux was used for all the welds. Copper levels for the two welds are 0.23 and 0.31 wt %, while the nickel contents for both welds are 0.60 wt %. Twelve capsules of specimens were irradiated in the pool-side facility of the Oak Ridge Research Reactor at a nominal temperature of 288{degree}C and an average fluence of about 1.5 {times} 10{sup 19} neutrons/cm{sup 2} (> 1 MeV). This volume, Appendices E and F, contains the load-displacement curves and photographs of the fracture toughness specimens from the 72W weld (0.23 wt % Cu) and the 73 W weld (0.31 wt % Cu), respectively.

  4. Effect of composition and processing on the thermal fatigue and toughness of high performance die steels. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, J.F.; Wang, Y.; Schwam, D.

    1997-06-01

    The objective of this study was to improve average die life by optimizing die steel composition and the die processing. Four different steels, K,Q,C and Premium Grade H-13 have been investigated for thermal fatigue resistance and toughness. Optimum heat treatment processing has been determined for each steel with respect to austenitizing temperature and tempering conditions. The effect of the quenching rate on the thermal fatigue resistance and toughness of the die steels and the effect of Electro-Discharge Machining (EDM) on the thermal fatigue resistance were also determined. The immersion thermal fatigue specimen developed at CWRU was used to determine the thermal fatigue resistance as characterized by the two parameters of average maximum crack length and total crack area. The Charpy V-notch impact test was used over a -100{degrees}F to 450{degrees}F testing temperature range to evaluate the toughness and the brittle-ductile transition behavior. K steel has been identified as superior in performance compared to Premium Grade H-13. Q and C provide lower toughness and thermal fatigue resistance than H-13. Faster cooling rates provide higher thermal fatigue resistance and toughness. Higher austenitizing temperatures such as 1925{degrees}F compared to 1875{degrees}F provide better thermal fatigue resistance, but lower austenitizing temperatures of 1875{degrees}F provide better toughness. Higher hardness improves thermal fatigue resistance, but reduces toughness. A minimum of Rc 46 hardness is desired for aluminum die casting dies. EDM reduces the thermal fatigue resistance compared to conventional machining operations. When the EDM process of multiple small steps of decreasing energy and post-EDM treatments are employed, the effect can be reduced to a very slight amount. Preliminary evidence of the superior performance of the K steel has been provided by ongoing field testing of inserts in multiple cavity dies.

  5. Production and fabrication of vanadium alloys for the radiative divertor program of DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, W.R.; Smith, J.P.; Stambaugh, R.D.

    1996-04-01

    V-4Cr-4-Ti alloy has been recently selected for use in the manufacture of a portion of the DIII-D Radiative Divertor modification, as part of an overall DIII-D vanadium alloy deployment effort developed by General Atomics (GA) in conjunction with the Argonne and Oak Ridge National Laboratories (ANL or ORNL). The goal of this work is to produce a production-scale heat of the alloy and fabricate it into product forms for the manufacture of a portion of the Radiative Divertor (RD) for the DIII-D tokamak, to develop the fabrications technology for manufacture of the vanadium alloy radiative Divertor components, and to determine the effects of typical tokamak environments in the behavior of the vanadium alloy. The production of a {approx}1300-kg heat of V-4Cr-4Ti alloy is currently in progress at Teledyne Wah Chang of Albany, oregon (TWCA) to provide sufficient material for applicable product forms. Two unalloyed vanadium ingots for the alloy have already been produced by electron beam melting of raw processes vanadium. Chemical compositions of one ingot and a portion of the second were acceptable, and Charpy V-Notch (CVN) impact test performed on processed ingot samples indicated ductile behavior. Material from these ingots are currently being blended with chromium and titanium additions, and will be vacuum-arc remelted into a V-4Cr-4Ti alloy ingot and converted into product forms suitable for components of the DIII-D RD structure. Several joining methods selected for specific applications in fabrication of the RD components are being investigated, and preliminary trials have been successful in the joining of V-alloy to itself by both resistance and inertial welding processes and to Inconel 625 by inertial welding.

  6. Thick-section weldments in 21-6-9 and 316LN stainless steel for fusion energy applications

    International Nuclear Information System (INIS)

    The Burning Plasma Experiment (BPX), formerly known as the Compact Ignition Tokomak, will be a major advance in the design of a fusion reactor. The successful construction of fusion reactors will require extensive welding of thick-section stainless steel plates. Severe service conditions will be experienced by the structure. Operating temperatures will range from room temperature (300 K) to liquid nitrogen temperature (77 K), and perhaps even lower. The structure will be highly stressed, and subject to sudden impact loads if plasma disruptions occur. This demands a combination of high strength and high toughness from the weldments. Significant portions of the welding will be done in the field, so preweld and postweld heat treatments will be difficult. The thick sections to be welded will require a high deposition rate process, and will result in significant residual stresses in the materials. Inspection of these thick sections in complex geometries will be very difficult. All of these constraints make it essential that the welding procedures and alloys be well understood, and the mechanical properties of the welds and their heat-affected zones must be adequately characterized. The candidate alloy for structural applications in the BPX such as the magnet cases was initially selected as 21-6-9 austenitic stainless steel, and later changed to 316LN stainless steel. This study examined several possible filler materials for thick-section (25 to 50 mm) weldments in these two materials. The tensile and Charpy V-notch properties were measured at room temperature and 77 K. The fracture toughness was measured for promising materials

  7. Heavy-section steel irradiation program: Embrittlement issues

    International Nuclear Information System (INIS)

    Maintaining the integrity of the reactor pressure vessel (RPV) in a light-water-cooled nuclear power plant is crucial in preventing and controlling severe accidents and the potential for major contamination releases. The RPV is one of only two major safety- related components of the plant for which a duplicate or redundant backup system does not exist. In particular, it is vital to fully understand the degree of irradiation-induced degradation of the RPV's fracture resistance which occurs during service, since without that radiation damage it is virtually impossible to postulate a realistic scenario which would result in RPV failure. For this reason, the Heavy-Section Steel Irradiation (HSSI) Program has been established by the US Nuclear Regulatory Commission (USNRC) to provide a thorough, quantitative assessment of the effects of neutron irradiation on the material behavior, and in particular the fracture toughness properties, of typical pressure vessel steels as they relate to light-water reactor pressure-vessel integrity. Effects of specimen size, material chemistry, product form and microstructure, irradiation fluence, flux, temperature and spectrum, and postirradiation annealing are being examined on a wide range of fracture properties including fracture toughness crack arrest toughness ductile tearing resistance Charpy V-notch impact energy, dropweight nil-ductility temperature and tensile properties. Models based on observations of radiation-induced microstructural changes using the field on microprobe and the high resolution transmission electron microscopy provide improved bases for extrapolating the measured changes in fracture properties to wider ranges of irradiation conditions. The principal materials examined within the HSSI program are high-copper welds since their postirradiation properties are most frequently limiting in the continued safe operation of commercial RPVs

  8. Genital impacts Genital impacts

    Directory of Open Access Journals (Sweden)

    Luiz Felipe G Soares

    2008-04-01

    Full Text Available I propose to analyze three images of genitalia from three different films that do not have sex as their central subject: (1 Lígia’s (Leona Cavalli’s vulva in Claudio Assis’s Amarelo Manga (Brazil, 2002, (2 Stoffer’s (Jens Albinus’s erect penis in Lars von Trier’s The Idiots (Denmark, 1998, and (3 transsexual Dil’s (Jaye Davidson’s penis in Neil Jordan’s The Crying Game (USA, 1992. All three images are explicit and surprising enough to provoke impact, both in diegetic and extra-diagetic spaces. intend to compare the three images and investigate the nature of their impacts, not directly in terms of morality, but in their relation with two theoretical assumptions: (1 the intense way in which, according to Linda Nicholson (1999, so many cultures insist in interpreting bodies and genitalia as still capable of defining gender characters, and (2 the notion of image, not as representation, but as image itself, as “what it is”, or as “the place of every transformation in the universe”, as suggested first by Bergson (2005, and then by Deleuze (1983-5, Rancière (2001 and Agamben (1995. The Deleuzean retard may indicate the way in which genitalia, as image, turn into enigma, in the very passage from nature to culture. The three shots give back to those clear images of genitalia the property they have always had: their character of central pieces in the game of such passage. The contrast between such simple and clear images and all those complex games corresponds to the nature of the impact I want to investigate. film; genitalia; narrative. I propose to analyze three images of genitalia from three different films that do not have sex as their central subject: (1 Lígia’s (Leona Cavalli’s vulva in Claudio Assis’s Amarelo Manga (Brazil, 2002, (2 Stoffer’s (Jens Albinus’s erect penis in Lars von Trier’s The Idiots (Denmark, 1998, and (3 transsexual Dil’s (Jaye Davidson’s penis in Neil Jordan’s The Crying Game (USA

  9. Genital impacts Genital impacts

    OpenAIRE

    Luiz felipe g. Soares

    2008-01-01

    I propose to analyze three images of genitalia from three different films that do not have sex as their central subject: (1) Lígia’s (Leona Cavalli’s) vulva in Claudio Assis’s Amarelo Manga (Brazil, 2002), (2) Stoffer’s (Jens Albinus’s) erect penis in Lars von Trier’s The Idiots (Denmark, 1998), and (3) transsexual Dil’s (Jaye Davidson’s) penis in Neil Jordan’s The Crying Game (USA, 1992). All three images are explicit and surprising enough to provoke impact, both in diegetic and extra-diaget...

  10. Impact behavior of 9-Cr and 12-Cr ferritic steels after low-temperature irradiation

    International Nuclear Information System (INIS)

    Miniature Charpy impact specimens of 9Cr-1MoVNb and 12Cr-1MoVW steels and these steels with 1 and 2% Ni were irradiated in the High-Flux Isotope Reactor (HFIR) at 500C to displacement damage levels of up to 9 dpa. Nickel was added to study the effect of transmutation helium. Irradiation caused an increase in the ductile-brittle transition temperature (DBTT). The 9Cr-1MoVNb steels, with and without nickel, showed a larger shift than the 12Cr-1MoVW steels, with and without nickel. The results indicated that helium also increased the DBTT. The same steels were previously irradiated at higher temperatures. From the present and past tests, the effect of irradiation temperature on the DBTT behavior can be evaluated. For the 9Cr-1MoVNb steel, there is a continuous decrease in the magnitude of the DBTT increase up to an irradiation temperature of about 4000C, after which the shift drops rapidly to zero at about 4500C. The DBTT of the 12Cr-1MoVW steel shows a maximum increase at an irradiation temperature of about 4000C and less of an increase at either higher or lower irradiation temperatures

  11. Impact behavior of reduced-activation steels irradiated to 24 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L.; Alexander, D.J. [Oak Ridge National Laboratory, TN (United States)

    1996-04-01

    Charpy impact properties of eight reduced-activation Cr-W ferritic steels were determined after irradiation to {approx}21-24 dpa in the Fast Flux Test Facility (FFTF) at 365{degree}C. Chromium concentrations in the eight steels ranged from 2.25 to 12wt% Cr (steels contained {approx}0.1%C). the 2 1/4Cr steels contained variations of tungsten and vanadium, and the steels with 5, 9, and 12% Cr, contained a combination of 2% W and 0.25% V. A 9Cr in FFTF to {approx}6-8 and {approx}15-17 dpa. Irradiation caused an increase in the DBTT and decrease in the USE, but there was little further change in the DBTT from that observed after the 15-17 dpa irradiation, indicating that the shift had essentially saturated with fluence. The results are encouraging because they indicate that the effect of irradiation on toughness can be faorably affected by changing composition and microstructure.

  12. Effect of heat treatment and cleanness of ultra low carbon bainitic (ULCB) steel on its impact toughness

    International Nuclear Information System (INIS)

    The small variations in sulphur and carbon concentrations can have a major influence on the impact transition temperature (ITT) of ultra low carbon HSLA-100 steel which has been quenched in water and tempered (WQ and T). Since the average carbon concentration is very low thus sensitivity of ITT to heat treatment parameters depends also on the yield strength increase due to precipitation effect of εCu phase. The regression analysis has been used to establish equations taking into account those parameters. The properties of a mixed microstructure formed from partially austenitic regions have been also considered. The fine austenitic grains transform into more desirable fine bainitic ferrite phases with lower hardness values and higher toughness. On the other hand, if cooling rate is sufficiently large, then the carbon enriched austenite transforms partially into hard martensite and some of remaining untransformed austenite being retained to ambient temperature. Because hard martensite islands are located in much softer surroundings consisting of tempered ferrite, they do not cause a general reduction in impact toughness tests. Due to further grain refinement of microstructure the measured toughness on Charpy V specimens can be very high at low temperatures. The very detrimental effect of sulphur in ULCB steel has been confirmed by presented results. (author)

  13. Soil Erosion and Surface Water Quality Impacts of Natural Gas Development in East Texas, USA

    OpenAIRE

    Matthew McBroom; Yanli Zhang; Todd Thomas

    2012-01-01

    Due to greater demands for hydrocarbons and improvements in drilling technology, development of oil and natural gas in some regions of the United States has increased dramatically. A 1.4 ha natural gas well pad was constructed in an intermittent stream channel at the Alto Experimental Watersheds in East Texas, USA (F1), while another 1.1 ha well pad was offset about 15 m from a nearby intermittent stream (F2). V-notch weirs were constructed downstream of these well pads and stream sedimentati...

  14. Injection moulding of long glass fibre reinforced poly(ethylene terephtalate: Influence of carbon black and nucleating agents on impact properties

    Directory of Open Access Journals (Sweden)

    E. Lafranche

    2012-09-01

    Full Text Available This paper aims at highlighting the influence of different additives (carbon black and nucleating agents on both the notched and unnotched Charpy impact properties of long glass fibre reinforced poly(ethylene terephtalate injection mouldings. The relationship with the polymer matrix and composite microstructure modifications (variations of crystalline morphology and local fibre content was investigated. Adding carbon black alone decreases the impact performances. This highly conductive additive actually increases the cooling rate, and therefore the fibre ‘frettage’ effect (higher internal stresses. It also acts as filler, which increases the material brittleness. The nucleating agents allow reducing the mould temperature, but their effect on the impact strength may be favourable or not depending on the processing temperatures. The addition of such additives induces perturbations of the polymer melt rheology in the mould cavity and of the cooling kinetics of the part, which both act on the fibre distribution during mould filling and on the degree of crystallinity of the composite parts.

  15. Impact Strength of Austenitic and Ferritic-Austenitic Cr-Ni Stainless Cast Steel in -40 and +20°C Temperature

    Directory of Open Access Journals (Sweden)

    Kalandyk B.

    2014-10-01

    Full Text Available Studies described in this paper relate to common grades of cast corrosion resistant Cr-Ni steel with different matrix. The test materials were subjected to heat treatment, which consisted in the solution annealing at 1060°C followed by cooling in water. The conducted investigations, besides the microstructural characteristics of selected cast steel grades, included the evaluation of hardness, toughness (at a temperature of -40 and +20oC and type of fracture obtained after breaking the specimens on a Charpy impact testing machine. Based on the results of the measured volume fraction of ferrite, it has been found that the content of this phase in cast austenitic steel is 1.9%, while in the two-phase ferritic-austenitic grades it ranges from 50 to 58%. It has been demonstrated that within the scope of conducted studies, the cast steel of an austenitic structure is characterised by higher impact strength than the two-phase ferritic-austenitic (F-A grade. The changing appearance of the fractures of the specimens reflected the impact strength values obtained in the tested materials. Fractures of the cast austenitic Cr-Ni steel obtained in these studies were of a ductile character, while fractures of the cast ferritic-austenitic grade were mostly of a mixed character with the predominance of brittle phase and well visible cleavage planes.

  16. Resistência ao impacto da madeira de nogueira-pecã em diferentes condições de umidade Impact strength of nogueira-pecã wood on different moisture conditions

    Directory of Open Access Journals (Sweden)

    Rafael Beltrame

    2012-09-01

    Full Text Available Os estudos de resistência da madeira ao impacto referem-se à eficiência com que este material absorve energia de um impacto e dissipa-a sem danos a sua estrutura. Dessa forma, o objetivo deste estudo foi avaliar a influência do teor de umidade na resistência ao impacto da madeira de nogueira-pecã (Carya illinoinensis. Para tanto, foram utilizadas árvores procedentes de duas regiões fisiográficas do estado do Rio Grande do Sul. Os corpos de prova, em condições de equilíbrio a 12% de umidade e saturados, foram submetidos ao impacto utilizando-se pêndulo de CHARPY, e avaliados quanto à resistência oferecida com a aplicação da carga nos planos tangencial e radial e posições de retirada (medula - casca nas toras, para as duas regiões fisiográficas em cada condição de umidade. Para auxiliar na interpretação dos dados, determinou-se a massa específica aparente a 12% e saturada, trabalho absorvido, coeficiente de resiliência e a cota dinâmica. Pôde-se verificar, por meio dos resultados, que a madeira de nogueira-pecã é mais resistente ao impacto na condição saturada.The studies of wood impact strength refers to the efficiency of this material in absorb impact energy and dissipate it without structural damages. The present study aimed to evaluate the influence of moisture content on the impact strength of nogueira-pecã (Carya illinoinensis wood. For this, trees from two physiographic regions of state of Rio Grande do Sul were used. The samples, stabilized at 12% of moisture content and in green conditions (saturated, were submitted to impact tests through a CHARPY pendulum, and were evaluated for the resistance to the application of loads in the tangential and radial sections, and in the positions of the log (pith-bark for the two physiographic regions at each moisture condition. Moreover, the apparent specific gravity at 12% and in green conditions (saturated, the absorbed work, the resilience coefficient and the

  17. Impact Toughness of 0.2 Pct C-1.5 Pct Si-(1.5 to 5) Pct Mn Transformation-Induced Plasticity-Aided Steels with an Annealed Martensite Matrix

    Science.gov (United States)

    Tanino, Hikaru; Horita, Masaomi; Sugimoto, Koh-Ichi

    2016-05-01

    The impact properties of 0.2 pct C-1.5 pct Si-(1.5 to 5) pct Mn transformation-induced plasticity (TRIP)-aided steels with an annealed martensite matrix which had been subjected to isothermal transformation after inter-critical annealing were investigated for potential automotive applications. The impact properties are related to the retained austenite characteristics of the steels. The products of tensile strength (TS) and Charpy impact absorbed value (CIAV) were the same for the 1.5 and 5 pct Mn steels, although the ductile-brittle transition temperature was higher for the latter. The impact properties of the 3 pct Mn steel were worse than these two steels. The high TS × CIAV value for the 5 pct Mn steel at 293 K (25 °C) was mainly caused by the TRIP effect of a larger amount of retained austenite (36 vol pct) and the hardened matrix structure; low retained austenite stability and/or a hard martensite-austenite phase reduced this value. The higher ductile-brittle transition temperature of the 5 pct Mn steel was associated with Mn segregation, a large amount of unstable retained austenite on prior austenitic grain boundaries, and decreased cleavage fracture stress owing to the high Mn content.

  18. Final Report, Volume 2, The Development of Qualification Standards for Cast Duplex Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Steven, W.; Lundin, Carl, W.

    2005-09-30

    The scope of testing cast Duplex Stainless Steel (DSS) required testing to several ASTM specifications, while formulating and conducting industry round robin tests to verify and study the reproducibility of the results. ASTM E562 (Standard Test Method for Determining Volume Fraction by Systematic manual Point Count) and ASTM A923 (Standard Test Methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic/Ferritic Stainless Steels) were the specifications utilized in conducting this work. An ASTM E562 industry round robin, ASTM A923 applicability study, ASTM A923 industry round robin, and an ASTM A923 study of the effectiveness of existing foundry solution annealing procedures for producing cast DSS without intermetallic phases were implemented. In the ASTM E562 study, 5 samples were extracted from various cast austenitic and DSS in order to have varying amounts of ferrite. Each sample was metallographically prepared by UT and sent to each of 8 participants for volume fraction of ferrite measurements. Volume fraction of ferrite was measured using manual point count per ASTM E562. FN was measured from the Feritescope® and converted to volume fraction of ferrite. Results indicate that ASTM E562 is applicable to DSS and the results have excellent lab-to-lab reproducibility. Also, volume fraction of ferrite conversions from the FN measured by the Feritescope® were similar to volume fraction of ferrite measured per ASTM E562. In the ASTM A923 applicability to cast DSS study, 8 different heat treatments were performed on 3 lots of ASTM A890-4A (CD3MN) castings and 1 lot of 2205 wrought DSS. The heat treatments were selected to produce a wide range of cooling rates and hold times in order to study the suitability of ASTM A923 to the response of varying amounts on intermetallic phases [117]. The test parameters were identical to those used to develop ASTM A923 for wrought DSS. Charpy V-notch impact samples were extracted from the castings and wrought

  19. Final Report, Volume 2, The Development of Qualification Standards for Cast Duplex Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Steven, W.; Lundin, Carl, D.

    2005-09-30

    The scope of testing cast Duplex Stainless Steel (DSS) required testing to several ASTM specifications, while formulating and conducting industry round robin tests to verify and study the reproducibility of the results. ASTM E562 (Standard Test Method for Determining Volume Fraction by Systematic manual Point Count) and ASTM A923 (Standard Test Methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic/Ferritic Stainless Steels) were the specifications utilized in conducting this work. An ASTM E562 industry round robin, ASTM A923 applicability study, ASTM A923 industry round robin, and an ASTM A923 study of the effectiveness of existing foundry solution annealing procedures for producing cast DSS without intermetallic phases were implemented. In the ASTM E562 study, 5 samples were extracted from various cast austenitic and DSS in order to have varying amounts of ferrite. Each sample was metallographically prepared by UT and sent to each of 8 participants for volume fraction of ferrite measurements. Volume fraction of ferrite was measured using manual point count per ASTM E562. FN was measured from the Feritescope{reg_sign} and converted to volume fraction of ferrite. Results indicate that ASTM E562 is applicable to DSS and the results have excellent lab-to-lab reproducibility. Also, volume fraction of ferrite conversions from the FN measured by the Feritescope{reg_sign} were similar to volume fraction of ferrite measured per ASTM E562. In the ASTM A923 applicability to cast DSS study, 8 different heat treatments were performed on 3 lots of ASTM A890-4A (CD3MN) castings and 1 lot of 2205 wrought DSS. The heat treatments were selected to produce a wide range of cooling rates and hold times in order to study the suitability of ASTM A923 to the response of varying amounts on intermetallic phases [117]. The test parameters were identical to those used to develop ASTM A923 for wrought DSS. Charpy V-notch impact samples were extracted from the

  20. The impact of hydrograph variability and frequency on the morphodynamics of gravel-bed rivers

    Science.gov (United States)

    Plumb, Ben; Franca, Mário; Juez, Carmelo; Schleiss, Anton; Annable, William

    2016-04-01

    Hydromodification is the alteration of natural watershed hydrologic processes, which is known to change the way that water naturally enters watercourses. In the case of urbanization, this change has manifested through individual hydrograph characteristics (resulting in a decrease in duration and in the time-to-peak), as well as through the increase of the frequency of morphologically significant flood events. These hydrologic changes have been documented to impact the morphology of gravel-bed rivers, often resulting in channel degradation. However, the actual extent that urbanization changes bedload transport characteristics, which is known to be the most important driver of channel morphology, are not yet known. A laboratory experiment was undertaken in a 0.5m gravel-bed flume with sediment feed using a single poorly sorted bimodal sediment mixture in order to evaluate the impacts of changing hydrograph characteristics and frequencies on bedload transport and bed morphology. The hydrograph characteristics and frequencies were derived from long term stream-gauge records of urbanizing gravel-bed watercourses. These records are long enough to therefore be representative of the actual relative changes of the hydrologic regime; from an unaltered to a highly hydromodified system. A series of four hydrologic scenarios were established, representing 10 years of morphologically significant discharge events for four different stages of urban land-use, and corresponding hydrologic regimes. Each scenario begins with the same initial conditions and is allowed to evolve naturally with each successive hydrograph. For each scenario, the hydrograph duration and unsteadiness were varied, while peak discharge remained constant for all scenarios. In addition, the number of hydrographs ranged from nine to 33 for the unaltered to the most hydromodified scenarios, respectively. Discharge was measured constantly with a v-notch weir, and varied with a calibrated valve relationship

  1. Impaction densitometer

    Energy Technology Data Exchange (ETDEWEB)

    Parrington, Josef R.

    2016-06-28

    Disclosed is an impaction densitometer having a chamber configured to receive a particle; a beam generator configured to emit a beam; a detector configured to receive the beam and convert a change in intensity of the received beam into an electrical signal corresponding to a particle volume; an impact sensor positioned a known distance from the beam and configured to measure a particle momentum as a function of an impact energy transferred from the particle to the impact sensor; a velocity calculator configured to calculate a particle velocity based on a time it takes the particle to pass through the beam and strike the impact sensor; a mass calculator configured to calculate a particle mass as a function of the particle momentum and velocity; and a density calculator configured to calculate a particle density as a function of the particle mass and volume.

  2. The evaluation of dynamic cracking resistance of chosen casting alloys in the aspect of the impact bending test

    Directory of Open Access Journals (Sweden)

    J.Sadowski

    2008-10-01

    Full Text Available The increase of quality and durability of produced casting alloys can be evaluated on the base of material tests performed on a high level. One of such modern test methods are tests of the dynamic damage process of materials and the evaluation on the base of obtained courses F(f, F(t of parameters of dynamic cracking resistance KId, JId, performed with the usage of instrumented Charpy pendulums. In the paper there was presented the evaluation of dynamic cracking resistance parameters of casting alloys such as: AK12 aluminum alloy, L20G cast steel and spheroid cast iron. The methodology of the evaluation of that parameters was described and their change as well, for the AK12 alloy with the cold work different level, L20G cast steel cooled from different temperatures in the range +20oC -60oC, and for the spheroid cast iron in different stages of treatment i.e. raw state, after normalization, spheroid annealing and graphitizing annealing.Obtained parameters of dynamic cracking resistance KId, JId of tested casting alloys enabled to define the critical value of the ad defect that can be tolerated by tested castings in different work conditions with impact loadings.

  3. Heat treatment effects on impact toughness of 9Cr-1MoVNb and 12Cr-1MoVW steels irradiated to 100 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1997-08-01

    Plates of 9Cr-1MoVNb and 12Cr-1MoVW steels were given four different heat treatments: two normalizing treatments were used and for each normalizing treatment two tempers were used. Miniature Charpy specimens from each heat treatment were irradiated to {approx}19.5 dpa at 365{degrees}C and to {approx}100 dpa at 420{degrees}C in the Fast Flux Test Facility (FFTF). In previous work, the same materials were irradiated to 4-5 dpa at 365{degrees}C and 35-36 dpa at 420{degrees}C in FFTF. The tests indicated that prior austenite grain size, which was varied by the different normalizing treatments, had a significant effect on impact behavior of the 9Cr-1MoVNb but not on the 12Cr-1MoVW. Tempering treatment had relatively little effect on the shift in DBTT for both steels. Conclusions are presented on how heat treatment can be used to optimize impact properties.

  4. Heat treatment effects on impact toughness of 9Cr-1MoVNb and 12Cr-1MoVW steels irradiated to 100 dpa

    International Nuclear Information System (INIS)

    Plates of 9Cr-1MoVNb and 12Cr-1MoVW steels were given four different heat treatments: two normalizing treatments were used and for each normalizing treatment two tempers were used. Miniature Charpy specimens from each heat treatment were irradiated to ∼19.5 dpa at 365 degrees C and to ∼100 dpa at 420 degrees C in the Fast Flux Test Facility (FFTF). In previous work, the same materials were irradiated to 4-5 dpa at 365 degrees C and 35-36 dpa at 420 degrees C in FFTF. The tests indicated that prior austenite grain size, which was varied by the different normalizing treatments, had a significant effect on impact behavior of the 9Cr-1MoVNb but not on the 12Cr-1MoVW. Tempering treatment had relatively little effect on the shift in DBTT for both steels. Conclusions are presented on how heat treatment can be used to optimize impact properties

  5. SCK-CEN Contribution to the''Relation between different measures of exposure-induced shifts in ductile-brittle transition temperatures'' (REFEREE). Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Chaouadi, R.; Van Walle, E.; Fabry, A.; Puzzolante, J.L

    1998-08-01

    The relationship between Charpy-V (CVN) impact, fracture toughness and tensile properties for selected reactor pressure -vessel steels in the transition temperature range are investigated. Data on the testing of unirradiated material are reported. The applied methods include chemical analysis, Charpy-V impact testing, tensile testing and fracture toughness determination.

  6. Evaluation of ductile-brittle transition behavior with neutron irradiation in nuclear reactor pressure vessel steels using small punch test

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M. C.; Lee, B. S. [KAERI, Taejon (Korea, Republic of); Oh, Y. J. [Hanbat National Univ., Taejon (Korea, Republic of)

    2003-10-01

    A Small Punch (SP) test was performed to evaluate the ductile-brittle transition temperature before and after neutron irradiation in Reactor Pressure Vessel (RPV) steels produced by different manufacturing (refining) processes. The results were compared to the standard transition temperature shifts from the Charpy test and Master Curve fracture toughness test in accordance with the ASTM standard E1921. The samples were taken from 1/4t location of the vessel thickness and machined into a 10x10x0.5mm dimension. Irradiation of the samples was carried out in the research reactor at KAERI (HANARO) at about 290 .deg. C of the different fluence levels respectively. SP tests were performed in the temperature range of RT to -196 .deg. C using a 2.4mm diameter ball. For the materials before and after irradiation, SP transition temperatures (T{sub sp}), which are determined at the middle of the upper and lower SP energies, showed a linear correlation with the Charpy index temperature, T{sub 41J}. T{sub sp} from the irradiated samples was increased as the fluence level increased and was well within the deviation range of the unirradiated data. The TSP had a correlation with the reference temperature (T{sub 0}) from the master curve method using a pre-cracked Charpy V-notched (PCVN) specimen.

  7. Economic impact

    Energy Technology Data Exchange (ETDEWEB)

    Technology Transfer Department

    2001-06-01

    In federal fiscal year 2000 (FY00), Berkeley Lab had 4,347 full- and part-time employees. In addition, at any given time of the year, there were more than 1,000 Laboratory guests. These guests, who also reside locally, have an important economic impact on the nine-county Bay Area. However, Berkeley Lab's total economic impact transcends the direct effects of payroll and purchasing. The direct dollars paid to the Lab's employees in the form of wages, salaries, and benefits, and payments made to contractors for goods and services, are respent by employees and contractors again and again in the local and greater economy. Further, while Berkeley Lab has a strong reputation for basic scientific research, many of the Lab's scientific discoveries and inventions have had direct application in industry, spawning new businesses and creating new opportunities for existing firms. This analysis updates the Economic Impact Analysis done in 1996, and its purpose is to describe the economic and geographic impact of Laboratory expenditures and to provide a qualitative understanding of how Berkeley Lab impacts and supports the local community. It is intended as a guide for state, local, and national policy makers as well as local community members. Unless otherwise noted, this analysis uses data from FY00, the most recent year for which full data are available.

  8. The use of single-specimen techniques for measuring upper shelf toughness properties under impact loading rates. Convention TRACTEBEL/SCK-CEN 2005 Task 1.1.5

    International Nuclear Information System (INIS)

    The multiple-specimen method (low-blow or stop-block tests) is the conventional approach for measuring the upper shelf fracture toughness of metallic materials under impact loading rates, typically fatigue precracked Charpy specimens tested on an instrumented pendulum machine. The method is fairly simple but requires a relatively large number of specimens. Nowadays, several single-specimen methods are available, which are purely based on the analysis of the instrumented force/displacement trace; they don't need any dedicated instrumentation for the measurement of crack extension during the test. Three of these techniques have been applied in this work to low-blow tests performed at different temperatures on two significantly different RPV steels (20MnMoNi55 and JSPS): the Normalization Data Reduction (NDR) technique, Schindler's Analytical 3-Parameter Approach and Chaouadi's method. Analyses have been performed after applying a double fitting approach to the raw test data, which allows selecting a limited set of force/displacement data which are representative of the whole instrumented trace. Results show that all three methods provide acceptable accuracy in terms of both ductile crack initiation and resistance to crack propagation (tearing modulus). However, for this type of analysis we recommend the use of the more widely accepted NDR technique, which is described in detail in the ASTM E1820-01 standard (although the limitations on data smoothness presently enforced in the standard seem incompatible with the oscillations of a typical dynamic PCCv curve). (author)

  9. Effect of Welding Speed and Tool Pin Geometry on Impact Strength in Friction Stir Welding of Aluminium 6101 T6 Alloy

    Directory of Open Access Journals (Sweden)

    Singh Rajbir

    2016-01-01

    Full Text Available Friction stir welding (FSW process is a solid state joining method in which the material that is being welded does not melt and recast. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters play a major role in deciding the joint characteristics. In this investigation the effect of welding speed and tool pin geometry in friction stir welds of Aluminium alloy was studied. The welded joints were made of Aluminium alloy AA 6101 T6 strips of 6mm thickness with different tool pin profile (Cylindrical, Taper cylindrical, Square and Taper Square. All the welding operations were done at the room temperature. Charpy tests were carried out to find the impact strength. From this investigation it is found that strength is superior with taper square tool pin profile than cylindrical, taper cylindrical and square tool pin profile. The pieces weld at rotational speed of 1200 r.p.m and welding speed of 70mm/min using taper square tool have higher strength.

  10. Notch position in the HAZ specimen of reactor pressure vessel steel

    Science.gov (United States)

    Kim, J. H.; Yoon, E. P.

    1998-12-01

    Variations in the notch toughness in the heat-affected zone (HAZ) were investigated by positioning the Charpy V-notches along the line normal to the weld fusion line of a SA 508 Cl.3 reactor pressure vessel (RPV) steel. In the notch position for common surveillance HAZ specimens, rather higher toughness values were acquired. The minimum properties were noted in the region of 4-5 mm apart from the fusion boundary, where the values of toughness and strength were both poorer than those of the other regions of the HAZ and the base metal. The causes for these variations were discussed with reference to the microstructures from the actual and the simulated welding processes.

  11. Standard Guide for Predicting Radiation-Induced Transition Temperature Shift in Reactor Vessel Materials, E706 (IIF)

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This guide presents a method for predicting reference transition temperature adjustments for irradiated light-water cooled power reactor pressure vessel materials based on Charpy V-notch 30-ftlbf (41-J) data. Radiation damage calculative procedures have been developed from a statistical analysis of an irradiated material database that was available as of May 2000. The embrittlement correlation used in this guide was developed using the following variables: copper and nickel contents, irradiation temperature, and neutron fluence. The form of the model was based on current understanding for two mechanisms of embrittlement: stable matrix damage (SMD) and copper-rich precipitation (CRP); saturation of copper effects (for different weld materials) was included. This guide is applicable for the following specific materials, copper, nickel, and phosphorus contents, range of irradiation temperature, and neutron fluence based on the overall database: 1.1.1 MaterialsA 533 Type B Class 1 and 2, A302 Grade B, A302 G...

  12. Current understanding of the effects of enviromental and irradiation variables on RPV embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    Odette, G.R.; Lucas, G.E.; Wirth, B.; Liu, C.L. [Univ. of California, Santa Barbara, CA (United States)

    1997-02-01

    Radiation enhanced diffusion at RPV operating temperatures around 290{degrees}C leads to the formation of various ultrafine scale hardening phases, including copper-rich and copper-catalyzed manganese-nickel rich precipitates. In addition, defect cluster or cluster-solute complexes, manifesting a range of thermal stability, develop under irradiation. These features contribute directly to hardening which in turn is related to embrittlement, manifested as shifts in Charpy V-notch transition temperature. Models based on the thermodynamics, kinetics and micromechanics of the embrittlement processes have been developed; these are broadly consistent with experiment and rationalize the highly synergistic effects of most important irradiation (temperature, flux, fluence) and metallurgical (copper, nickel, manganese, phosphorous and heat treatment) variables on both irradiation hardening and recovery during post-irradiation annealing. A number of open questions remain which can be addressed with a hierarchy of new theoretical and experimental tools.

  13. Analysis of fracture toughness in transition temperature region of a Mn-Mo-Ni low-alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Ho; Hwang, Byoung Chul; Lee, Sung Hak [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of)

    2002-08-01

    This study is concerned with the analysis of fracture toughness in the transition region of a Mn-Mo-Ni low-alloy steel according to ASTM E1921 standard test method. Elastic-plastic cleavage fracture toughness, K{sub Jc} was determined by 3-point bend tests, using precracked Charpy V-notch (PCVN) specimens, and then the measured K{sub Jc} values were interpreted by the 3-parameter Weibull distribution with a theoretical slope of 4. fractographic observation indicated that the critical distance from a precrack tip to a cleavage initiation site linearly increased with increasing the critical J(J{sub c}) value, and that the stretch zone width had a good correlation with K{sub Jc} value, irrespective of testing temperature. Relationship between J{sub c} and critical distance, local fracture stress, and plane strain fracture toughness were discussed on the basis of the cleavage fracture behavior in the transition temperature region.

  14. Applicability of master curve concept for the safety assessment of power plant components - experimental investigations

    Energy Technology Data Exchange (ETDEWEB)

    Tanguy, B.; Stoeckl, H.; Siegele, D. [Fraunhofer-Institut fuer Werkstoffmechanik (IWM), Freiburg im Breisgau (Germany)

    2003-07-01

    This paper presents the application of the master curve concept to the determination of the reference temperature, T{sub 0} for two different reactor pressure vessel (RPV) steels. The aim of this study is to provide a wide experimental database and microstructural observations to study the applicability of master curve concept. Mechanical and fracture properties of 22NiMoCr3-7 and JRQ A533B steels have been investigated over a wide range of temperatures. Precracked Charpy V-notch (PCVN) and CT(1T) specimens were used to characterize the fracture toughness of two unirradiated reactor pressure vessel steels. The master curve methodology described in ASTM Standard E1921 was followed to determine the reference temperature, T{sub 0}. The reference temperature dependence on specimen geometry and on specimen location was evidenced. A systematic investigation of the nature and position of cleavage initiating sites has been carried out. (orig.)

  15. Mechanical and Microstructural Evaluation of DMAG Welding of Structural Steel

    Directory of Open Access Journals (Sweden)

    Tolga Mert

    2015-01-01

    Full Text Available Double channel torch, which allows concentric flow of two different shielding gases, was designed and manufactured in order to pursue double channel torch gas metal arc welding of unalloyed structural steel S235JR (EN 10025-2 with fourteen passes. Tensile and Charpy V-notch tests were realized and the results were compared with those of conventional gas metal arc welding. In order to evaluate mechanical testing results, microstructural analyses were conducted. It was found that the increase with double channel gas metal arc welding process in yield and tensile strengths as well as in toughness tests, especially in subzero temperatures, compared with conventional gas metal arc welding was due to longer columnar grains and finer tempered zone grain structure between passes and due to solidification and less dendritic structure formation in all-weld metal in double channel gas metal arc welding.

  16. Microstructural changes and fracture behavior of CF8M duplex stainless steels after long-term aging

    International Nuclear Information System (INIS)

    Microstructural changes and fracture behavior in cast CF8M duplex stainless steel after aging at 300-450 C for 300-10000 h have been investigated. Both, optical microscopical and transmission electron microscopical analyses, hardness and ferrite content measurements have been carried out in this study. Strengthening and aging phenomena of the ferrite phase have been identified by hardness measurements. Spinodal decomposition and heterogeneous precipitation of G-phase were found to be responsible for strengthening of the ferrite phase after aging with a temper parameter [P=log(t)+0.4343 Q/R(1/673.2-1/4)] (see Appendix A) in the range ca. 1.8-4.5. Three different fracture modes, dimples, cleavage and α/γ grain boundary separation, have been observed for Charpy V-notch and CT test specimens fractured at 20 C. (orig.)

  17. Weld metal toughness - sources of variation

    Energy Technology Data Exchange (ETDEWEB)

    Quintana, Marie; Major, Jeff; Dallam, Craig; James, Matt [Lincoln Electric, Cleveland, OH, (United States); Babu, S. S. [Ohia State University, Columbus, OH, (United States)

    2010-07-01

    The measurement of weld toughness is largely studied using Charpy V-notch (CVN), but the CVN toughness values can vary widely in the same weld. This study investigated the causes of such variations in CVN measurements. Several CVN tests, a microstructure analysis and nanohardness measurements were performed to identify the microstructural properties affecting the CNV toughness values. The results showed that the CVN toughness values are controlled by local microstructure conditions. The size of austenite grain and ferritic microstructures are conditioned by cooling conditions. It is shown that the highly localized regions of coarse-grained ferrite are associated with the lowest CVN toughness measurements. It is also shown that the transformation of austenite into martensite under the load and reduced temperature associated with coarse ferrite microstructure explain the magnitude in CVN results.

  18. Development and Optimization of High-Resolution Neutron Scattering Instruments Dedicated to Characterization and Testing of Materials of Relevance to Nuclear Energy Sector and Related Experiments in SANS, Residual Strain/Stress and Texture Studies

    International Nuclear Information System (INIS)

    In this report we present the results we have received in the frame of participation in the CRP project. According to the plan of the project several experiments related namely to characterisation and testing of materials of relevance to nuclear sector were carried out. In this way two experimental methods were used: residual strain/stress measurements by neutron diffraction and small angle neutron scattering (SANS). A special attention has been paid to the following samples: Austenitic stainless steel plates with a longitudinal weld joint, Charpy-V notched specimen of low-alloy ferritic steel, 50 mm thick welds in feritic steel, austenitic single pass fillet steel welds, Ni-based CMSX4 superalloy. (author)

  19. Effects of thermal aging and neutron irradiation on the mechanical properties of stainless steel weld overlay cladding

    International Nuclear Information System (INIS)

    Stainless steel weld overlay cladding was fabricated using the three-wire, series-arc method. Three layers of cladding were applied to a pressure vessel plate to provide adequate thickness for fabrication of test specimens. Since irradiation of the stainless steel cladding to 5 x 1019 neutrons/cm2 (>1 MeV) was conducted at 288 degrees C for 1605 h, tensile, Charpy V-notch (CVN), precracked Charpy V-notch (PCVN), and compact fracture toughness specimens were thermally aged at 288 degrees C for 1605 h. Additional specimens are being aged to 20,000 and 50,000 h. Thermal aging of three-wire, series-arc stainless steel weld overlay cladding at 288 degrees C for 1604 h resulted in appreciable decrease (16%) in the CVN upper-shelf energy, but the effect on the 41-J transition temperature shift was very small (3 degrees C). The combined effect, following neutron irradiation at 288 degrees C to a fluence of 5 x 1019 neutrons/cm2 (>MeV), was a 22% reduction in the CVN upper-shelf energy and a 29 degrees C shift at the 41-J level. The effect of thermal aging on tensile properties was very small or negligible. However, the combined effect after neutron irradiation was an increase in the yield strength (6 to 34% at test temperatures from 288 to -125 degrees C) and no apparent change in ultimate strength and total elongation. Also, neutron irradiation reduced the initiation fracture toughness (JIc) much more than did thermal aging. However, irradiation slightly decreased the tearing modulus, but no reduction was caused by thermal aging alone. The effects of long-term thermal exposure times (20,000 and 50,000 h) will be investigated when the specimen become available

  20. Evaluation of ductile-brittle transition temperature before and after neutron irradiation for RPV steels using small punch tests

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min-Chul [Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)]. E-mail: mckim@kaeri.re.kr; Oh, Yong Jun [Hanbat National University, Deogmyeong-dong, Yuseong-gu, Daejeon 305-719 (Korea, Republic of); Lee, Bong Sang [Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2005-08-01

    Small punch (SP) tests were performed to evaluate the ductile-brittle transition temperature before and after a neutron irradiation of reactor pressure vessel (RPV) steels produced by different manufacturing (refining) processes. The results were compared to the standard transition temperature shifts from the conventional Charpy tests and the Master Curve fracture toughness tests in accordance with the American Society for Testing and Materials (ASTM) standard E1921. Small punch specimens were taken from a 1/4t location of the vessel thickness and machined into a 10 mm x 10 mm x 0.5 mm dimension. The specimens were irradiated in the research reactors at Korea Atomic Energy Research Institute Nuclear Research Institute in the Czech Republic at the different fluence levels of about 290 deg C. Small punch tests were performed in the temperature range of RT to -196 deg C using a 2.4 mm diameter ball. For the materials before and after irradiation, the small punch transition temperatures (T {sub SP}), which are determined at the middle of the upper small punch energies, showed a linear correlation with the Charpy index temperature, T {sub 41J}. T {sub SP} from the irradiated samples was increased with the fluence levels and was well within the deviation range of the unirradiated data. However, the transition temperature shift from the Charpy test ({delta}T {sub 41J}) shows a better correlation with the transition temperature shift ({delta}T {sub SP(E)}) when a specific small punch energy level rather than the middle energy level of the small punch curve is used to determine the transition temperature. T {sub SP} also had a correlation with the reference temperature (T {sub 0}) from the Master Curve method using a pre-cracked Charpy V-notched (PCVN) specimen.

  1. Efeito do tratamento térmico de solubilização na microestrutura e nas propriedades de impacto do aço inoxidável superaustenítico ASTM A 744 Gr. CN3MN Aging heat treatment effect on the microstructure and impact properties of the super-austenitic stainless steel ASTM A 744 Gr. CN3MN

    Directory of Open Access Journals (Sweden)

    Márcio Ritoni

    2010-03-01

    Full Text Available O aço inoxidável superaustenítico ASTM A 744 Gr. CN3MN é aplicado na fabricação de equipamentos que trabalham em ambientes sob corrosão severa com solicitação mecânica. Nesse trabalho investigou-se a influência do tratamento térmico de solubilização na microestrutura e nas propriedades desse tipo de material. Foram realizados tratamentos térmicos de solubilização na faixa de temperaturas entre 1100 e 1250°C. Ensaios de impacto (Charpy em temperatura ambiente e a -46°C foram realizados nas amostras tratadas termicamente. As análises microestruturais foram feitas por meio de microscopia eletrônica de varredura, eletrônica de transmissão e difração de raios X. Concluiu-se que, para maximizar a resistência ao impacto, a solubilização deve ser feita a 1200°C, pois tal medida produz a menor fração volumétrica de precipitados. As amostras solubilizadas a 1200 e 1240°C apresentaram fase sigma (s e carboneto M6C.This research investigated the influence of solution heat treatments on the microstructure and properties of this type of material. These treatments were carried out at temperatures ranging from 1100 to 1250ºC. Impact (Charpy tests were conducted at room temperature and -46°C for all solution treated samples. The microstructural analyses were carried out by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. It was concluded that, to maximize the material's impact strength, the solution heat treatment should be done at 1200ºC, at which temperature the volumetric fraction of precipitates is lower than at other solution heat treatment temperatures. The samples that were solution heat treated at 1200 and 1240ºC presented sigma (s and M6C carbide phases.

  2. Fractal characterization of impact strength fracture of bamboo plastic composites with core-shell structure%芯壳结构竹塑复合材料断口冲击强度的分形表征

    Institute of Scientific and Technical Information of China (English)

    羡瑜; 王翠翠; 王戈; 程海涛

    2015-01-01

    In order to study the rupture mechanism of the bamboo plastic composites (BPCs) with core-shell structure, in this paper bamboo residue fibers and high density polyethylene (HDPE) were used as materials of core layer; HDPE, bamboo pulp fibers/HDPE, nano-CaCO3/HDPE and white mud/HDPE, were respectively used as materials of shell layer to manufacture the BPCs with core-shell structure by coextrusion technology. The ratios of bamboo pulp fibers, nano-CaCO3 and white mud to HDPE in the shell layer structure were to be 10:90 respectively. To present the theoretical relationship between fractal dimensions (D) and the impact strength (δ), and analyze the effects of different shell layer materials on the impact strength in the BPCs with core-shell structure, Charpy non-notched impact strength of the BPCs with core-shell structure was measured at room temperature according to ASTMD6110-2010. The fractographs of the BPCs with core-shell structure that had different shell layer materials were observed by scanning electron microscope (SEM). The impact fracture surface topography of BPCs manifested self-similarity. Based on fractal theory and computer image processing technology, a MATLAB program which computed the fracture’s box-counting dimension of the BPCs with core-shell structure was designed. The digital image was transformed into factual image, and the charpy impact fracture surface fractal dimensions of the BPCs with core-shell structure that had different shell layer materials were measured by pixel-covering method, to investigate the relationship between impact strength and fractal dimension of the BPCs with core-shell structure. Results showed that the BPCs fracture possessed fractal characteristics and there were differences for the fractal dimensions of the BPCs with core-shell structure that had different shell layer materials. The fractal dimensions of the fracture surface were within the range of from 2.2075 to 2.2204, the linear degree of fitted beeline of

  3. Effect of lead factors on the embrittlement of RPV SA-508 cl 3 steel

    International Nuclear Information System (INIS)

    This paper presents a project to study the effect of lead factors on the mechanical behaviour of the SA-508 type 3 Reactor Pressure Vessel (RPV) steel used in the reactor under construction Atucha II in Argentina. Charpy-V notch specimens of this steel were irradiated at the RA1 experimental reactor at a temperature of 275 °C with two lead factors (186 and 93). The neutron flux was 3.71 × 1015 n m−2 s−1 and 1.85 × 1015 n m−2 s−1 (E > 1 MeV) respectively. In both cases, the fluence was 6.6 × 1021 n m−2, which is equivalent to that received by the PHWR Atucha II RPV in 10 years of full power irradiation. The results of Charpy tests revealed significant embrittlement both in the ΔT = 14 °C and ΔT = 21 °C shifts of the ductile–brittle transition temperatures (DBTT) and in the reduction of the maximum energy absorbed. This result shows that the shift of the DBTT with a lead factor of 93 is larger than that obtained with a lead factor of 186. Then, the results of irradiation in experimental reactors (MTR) with high lead factors may not be conservative with respect to the actual RPV embrittlement

  4. Influence of delta ferrite content and welding variables on notch toughness of austenitic stainless steel weldments

    International Nuclear Information System (INIS)

    Two series of austenitic stainless steel weld deposits are evaluated to explore the separate contributions of delta ferrite content and welding variables to apparent notch toughness. Charpy-V and Dynamic Tear test determinations are used for weld deposit comparisons. The investigation represents the first part of a two part study of variable weld notch toughness in preirradiation and postirradiation conditions for the temperature range 750F (240C) to 11000F (5930C). Weld Series 1, represented by four 21/2-in. thick AISI Type 308 weld deposits (shielded metal arc) exhibited delta ferrite contents ranging from ferrite number 5.2 to 19.0. Variations in delta ferrite content within this range did not appear to be a major factor in observed toughness trends. Weld Series 2, formed of six 1-in. thick AISI Type 316 weld deposits (submerged arc), indicated that welding parameters and minor differences in flux lot formulations can contribute to variable notch toughness. Initial radiation tests demonstrate that a fluence of 8 to 9 x 1019 n/cm2 greater than 0.1 MeV at 500 to 5500F (260 to 2880C) can produce large reductions in Charpy-V notch ductility for Types 308 and 316 weld deposits

  5. Effect of lead factors on the embrittlement of RPV SA-508 cl 3 steel

    Energy Technology Data Exchange (ETDEWEB)

    Kempf, Rodolfo, E-mail: kempf@cnea.gov.ar [CNEA, Unidad Actividad Combustibles Nucleares, División Caracterización, Avda. Gral Paz 1499, C.P.B1650KNA, San Martín, Buenos Aires (Argentina); Troiani, Horacio, E-mail: troiani@cab.cnea.gov.ar [Centro Atómico Bariloche (CNEA) e Instituto Balseiro (UNCU), CONICET, Av. Bustillo 9500, CP 8400, Rio Negro (Argentina); Fortis, Ana Maria, E-mail: fortis@cnea.gov.ar [CNEA, Departamento Estructura y Comportamiento, UNSAM, Avda. Gral Paz 1499, C.P.B1650KNA, San Martín, Buenos Aires (Argentina)

    2013-03-15

    This paper presents a project to study the effect of lead factors on the mechanical behaviour of the SA-508 type 3 Reactor Pressure Vessel (RPV) steel used in the reactor under construction Atucha II in Argentina. Charpy-V notch specimens of this steel were irradiated at the RA1 experimental reactor at a temperature of 275 °C with two lead factors (186 and 93). The neutron flux was 3.71 × 10{sup 15} n m{sup −2} s{sup −1} and 1.85 × 10{sup 15} n m{sup −2} s{sup −1} (E > 1 MeV) respectively. In both cases, the fluence was 6.6 × 10{sup 21} n m{sup −2}, which is equivalent to that received by the PHWR Atucha II RPV in 10 years of full power irradiation. The results of Charpy tests revealed significant embrittlement both in the ΔT = 14 °C and ΔT = 21 °C shifts of the ductile–brittle transition temperatures (DBTT) and in the reduction of the maximum energy absorbed. This result shows that the shift of the DBTT with a lead factor of 93 is larger than that obtained with a lead factor of 186. Then, the results of irradiation in experimental reactors (MTR) with high lead factors may not be conservative with respect to the actual RPV embrittlement.

  6. Experimental study on mechanical properties and impact toughness of steel for transmission line towers at low temperatures%输电线铁塔钢材的低温力学和冲击韧性试验

    Institute of Scientific and Technical Information of China (English)

    王元清; 廖小伟; 张子富; 刘希月; 邢海军

    2015-01-01

    为选择合适的输电线铁塔钢材,防止杆塔因构件发生低温脆性断裂引起的破坏,通过系列室温和低温条件下的单轴拉伸和冲击试验,研究了输电线铁塔用Q345B、Q420B、Q460C钢管和Q345B、Q420B角钢钢材的力学性能和冲击韧性;通过对比分析,评价了钢管和角钢钢材的塑性指标;利用Boltzmann函数曲线拟合,得到了钢管和角钢钢材的韧-脆转变温度.结果表明:钢材的屈服强度和抗拉强度随温度的降低而增大,其塑性指标均能满足规范要求;钢材夏比冲击功值随温度降低而减小, Q345B钢管和角钢钢材的韧脆转变温度较高,抗低温冷脆性能较差,结合拉伸和冲击试验结果,建议在寒冷地区优先采用Q420B钢管,不宜采用Q345B角钢.%In cold region, it is of great significance to select suitable steel material in order to prevent the failure or collapse of transmission line tower, which results from the brittle fracture of construction member at low temperatures . A series of uniaxial tensile tests and Charpy impact tests were performed to investigate the mechanical properties and impact toughness of materials of steel tube ( Q345B, Q420B, Q460C ) and angle iron ( Q345B, Q420B) . The plastic indices of steel tube and angle iron materials were evaluated through comparison and analysis. The Boltzmann function was employed to conduct curve fitting for impact energy versus temperature, obtaining the ductile-brittle transition temperatures. Results indicate that the yield strength and ultimate tensile strength increase with the decrease of temperature, and all the plastic indices can meet the prescribed requirement. Charpy impact energy increases as the temperature reduces. Besides, the ductile-brittle transition temperatures of Q345B steel tube and Q345B angle iron are relatively high, indicating the poor resistance ability of cold brittleness failure. Based on the results of tensile tests and impact tests, it is suggested that

  7. Felled trees as a rockfall protection system: Impact on simply supported fresh wood stems, experimental and numerical study

    Science.gov (United States)

    Olmedo, Ignacio; Bourrier, Franck; Bertrand, David; Berger, Frédéric; Limam, Ali

    2014-05-01

    Forest is a well known and efficient natural protection solution against rockfall. In forested areas, the maintenance of forests is required to ensure their protective function and health. During this process that consists in removing some trees, the protective capacity of the forest decreases. To compensate the temporary loss of protection, some of the felled trees can be left in an oblique position to the slope. It is a financially feasible solution to ensure the protection against rockfall during the regeneration of forests. Thus, felled trees can become a useful protection system if they are correctly placed. No studies have been done concerning the efficiency of these devices and particularly their resistance to rock impacts and their energy dissipation capacity. In order to estimate the capacity of these devices to dissipate energy, it is necessary to study the dynamic response of tree stems under impact as well as rock's trajectory changes due the interaction with such structures. Experimental and numerical studies are carried out to determine the efficacy of this devices. Laboratory experiments enabled studying the response of fresh wood stems under dynamic and quasi-static loadings. A Mouton-Charpy pendulum was used on the dynamic loading tests performed onto simply supported stems. The experimental device was instrumented in order to obtain the impact force data and the stem's displacements fields. The mechanical properties of fresh wood are analyzed from the experimental results which also allow carrying out a detailed study of the stems dynamic response. A numerical model based on the Discrete Element Method (DEM) enables to simulate the interaction of a rock and a felled tree device. To simulate the rock - tree interactions, rocks are represented by spherical solid bodies while cylindrical bodies represent the trees. The fresh wood constitutive law and the contact law are integrated on the model allowing realistic simulations. The numerical model is

  8. Effect of neutron irradiation on the impact properties of A533B steel

    International Nuclear Information System (INIS)

    A new methodology is proposed to correlate the upper shelf energy (USE) of full size and subsize Charpy specimens of a nuclear reactor pressure vessel plate material, ASTM type A 533 Grade B (A533B) having a low USE (USE 19 n/cm2 (E > 1 MeV) by 78 degree, 83 degree, and 70 degree C for full, half, and third size specimens, respectively. These shifts in DBTT appeared to be independent of specimen size and notch geometry

  9. Chicxulub Ejecta Impact Trenches And Terminal Impact

    Science.gov (United States)

    Page, R. L.

    2013-05-01

    DISCOVERY During a Pacific voyage from E. Australia to the US on a small sailing research vessel what appears to be two Chicxulub impact trenches were discovered in the ocean floor at depths of 4,627m and 3,519m. DESCRIPTION Trench A begins at a depth of 4,627m, 704km from the Chicxulub impact and is 18km long, 5km wide and 225m deep. Trench B begins at a depth of 3,519m, 732km from the Chixculub impact and is 23km long, 7 km wide and 400m deep. At the end of Trench B is what appears to be a debris deposit 5km long. Their relationship to the Chicxulub impact seems confirmed by their central axis, which when extended intersect at the Chicxulub impact at N Lat 21.33, W Long 89.5. Down range 286km from the end of Trench B is what appears to be the terminal impact of the object that created the two trenches. This is in the form of several large boulders, small seamounts, and islands in shallower depths indicating breakup of the object 1040km from the Chicxulub impact. The trenches are in an area of the Caribbean where currents prevented them from being silted in, preserving their physical form on the ocean floor. The object that created the trenches could have been large ejecta from the impact or possibly part of the asteroid that separated before impact or upon impact and carried on 1000km down range. The trajectory of both trenches is an upward angle of about 3 degrees. This indicates that the trajectory of the object was at a low angle, very high velocity and was deflected slightly upward upon impact with the ocean floor 4,627 below sea level. RESEARCH The first two phases of 10 phases consisting of mapping, exploration, research, and documentation of the impacts have been completed. Phase 1 consisted of assembling available sea floor data of the area of the impacts. Phase 2 consisted of selecting aerial and under water images from Google Earth, preparing bathymetric mapping from a GEBCO_08. BODC raster analysis with 50m contour intervals of the impact area

  10. Impacted science: impact is not importance.

    Science.gov (United States)

    Casadevall, Arturo; Fang, Ferric C

    2015-10-13

    The journal impact factor (IF) exerts a tremendous influence on the conduct of scientists. The obsession with IF has been compared to a medical condition, sometimes referred to as "IF mania" or "impactitis." Here, we analyze the difference between impact and importance, using examples from the history of science to show that these are not equivalent. If impact does not necessarily equal importance, but scientists are focused on high-impact work, there is a danger that misuse of the IF may adversely affect scientific progress. We suggest five measures to fight this malady: (i) diversify journal club selections, (ii) do not judge science on the publication venue, (iii) reduce the reliance on journal citation metrics for employment and advancement, (iv) discuss the misuse of the IF in ethics courses, and (v) cite the most appropriate sources. If IF mania is indeed a medical condition, the most appropriate course of action may be disimpaction.

  11. Socioeconomic impacts of gambling

    OpenAIRE

    Huovila, Antti

    2014-01-01

    The thesis discusses the social and economic impacts associated with legalized gambling. The purpose of the study is to analyze what are the relevant impacts of gambling and how they are studied in academic literature. The main focus is in the examination of the potential social costs that derive from problem gambling and gambling related crime. Other social and economic impacts are analyzed as well in order to assess the overall impacts of legalized gambling. The thesis is conducted as a...

  12. Assessing climate impacts

    OpenAIRE

    Wohl, Ellen E.; Roger S. Pulwarty; Zhang, Jian Yun

    2000-01-01

    Assessing climate impacts involves identifying sources and characteristics of climate variability, and mitigating potential negative impacts of that variability. Associated research focuses on climate driving mechanisms, biosphere–hydrosphere responses and mediation, and human responses. Examples of climate impacts come from 1998 flooding in the Yangtze River Basin and hurricanes in the Caribbean and Central America. Although we have limited understanding of the fu...

  13. Impacted wisdom teeth

    OpenAIRE

    Dodson, Thomas B.; Susarla, Srinivas M.

    2010-01-01

    Impacted wisdom teeth occur because of a lack of space, obstruction, or abnormal position. They can cause pain, swelling, and infection, and may destroy adjacent teeth and bone.The incidence of impacted wisdom teeth is high, with some 72% of Swedish people aged 20 to 30 years having at least one impacted third molar.

  14. X70焊管焊接接头热影响区冲击试样缺口位置的探讨%Discussion on Impact Specimen Notch Position of X70 Welded Pipe Heat Affected Zone(HAZ)

    Institute of Scientific and Technical Information of China (English)

    王丽丽; 刘通; 王自信; 顾志乾

    2015-01-01

    In this article, it studied the distribution situation of metallographic structure, impact energy and shearing area of X70 SAWH pipe welded joint HAZ specimen in different Notch position, by adopting metallographic test and Charpy impact test. The results indicated that the values of impact energy value and shearing area are related with Notch position proportion in coarse grained region, fine grained region, part of the phase change zone and inside weld. The lower the proportion of inside weld is, the greater the impact energy and shearing area. After comprehensive analysis of test results and related standards, the determination method of X70 SAWH pipe welded joint HAZ specimen Notch position was obtained; the Notch axis of HAZ impact specimen should be in the junction of specimen upper surface and outside weld fusion line, and the distance from Impact test specimen edges to the outside weld edge of 1~2 mm is applicable.%通过金相试验、夏比冲击试验研究了X70螺旋埋弧焊管焊接接头热影响区试样不同缺口位置的金相组织、冲击功及剪切面积的分布情况。试验结果显示,冲击功和剪切面积的大小与缺口位置在粗晶区、细晶区、部分相变区和内焊缝所占的比例相关,内焊缝所占比例越低,冲击功和剪切面积越大。综合分析试验结果和相关标准,得出了X70焊管焊接接头热影响区试样缺口位置的确定方法,即热影响区冲击试样的缺口轴线应在试样上表面与外焊缝熔合线交界处,冲击试样边缘距外焊缝边缘1~2 mm为宜。

  15. Head Impact Laboratory (HIL)

    Data.gov (United States)

    Federal Laboratory Consortium — The HIL uses testing devices to evaluate vehicle interior energy attenuating (EA) technologies for mitigating head injuries resulting from head impacts during mine/...

  16. Impact assessment revisited

    DEFF Research Database (Denmark)

    Thiele, Jan; Kollmann, Johannes Christian; Markussen, Bo;

    2010-01-01

    The theoretical underpinnings of the assessment of invasive alien species impacts need to be improved. At present most approaches are unreliable to quantify impact at regional scales and do not allow for comparison of different invasive species. There are four basic problems that need to be addre......The theoretical underpinnings of the assessment of invasive alien species impacts need to be improved. At present most approaches are unreliable to quantify impact at regional scales and do not allow for comparison of different invasive species. There are four basic problems that need...... to be addressed: (1) Some impacted ecosystem traits are spatially not additive; (2) invader effects may increase non-linearly with abundance or there may be effect thresholds impairing estimates of linear impact models; (3) the abundance and impact of alien species will often co-vary with environmental variation......; and (4) the total invaded range is an inappropriate measure for quantifying regional impact because the habitat area available for invasion can vary markedly among invasive species. Mathematical models and empirical data using an invasive alien plant species (Heracleum mantegazzianum) indicate...

  17. Impact studies at Winfrith

    International Nuclear Information System (INIS)

    Analytical and experimental studies of subsonic impacts on nuclear reactor plant structures have been in progress at Winfrith since 1977. These studies have examined the behaviour of concrete and metal structures under the impact of missiles typifying those derived either from the plant itself or from external sources, such as crashing aircraft. During 1986 the Winfrith programme was expanded to include studies of the behaviour of radioactive materials transport containers under impact conditions. This report initially describes the experimental facilities available for impact studies at Winfrith. These include both compressed air guns, capable of delivering payloads of up to 65 kg at sonic velocity or payloads up to 2 tonnes at speeds up to 45 ms-1, and drop test facilities for impact testing of models, up to full-scale radioactive materials transport flasks, at relatively low speeds. Supporting facilities include a small concrete manufacturing laboratory to produce concrete targets. Assessments of the resistance of concrete or metal structures to impact damage are performed using empirical or semi-empirical correlations, derived from data obtained in well-characterised experiments, or using structural dynamics finite element codes. The codes used by the analysts and the computing facilities available for impact analysis work are described. Finally the current programme of impact studies is reviewed, recent progress is summarised and future plans outlined. (author)

  18. Deep Impact Spots Quarry

    Science.gov (United States)

    2005-01-01

    Sixty-nine days before it gets up-close-and-personal with a comet, NASA's Deep Impact spacecraft successfully photographed its quarry, comet Tempel 1, at a distance of 39.7 million miles. The image, taken on April 25, 2005, is the first of many comet portraits Deep Impact will take leading up to its historic comet encounter on July 4.

  19. Neutron spectra at different High Flux Isotope Reactor (HFIR) pressure vessel surveillance locations

    Energy Technology Data Exchange (ETDEWEB)

    Remec, I. [Josef Sefan Inst., Ljubljana (Slovenia); Kam, F.B. [Oak Ridge National Lab., TN (United States)

    1993-12-01

    This project addresses the potential problem of radiation embrittlement of reactor pressure vessel (RPV) supports. Surveillance specimens irradiated at the High Flux Isotope Reactor (HFIR) at relatively low neutron flux levels (about 1.5E + 8 cm{sup {minus}2}.s{sup {minus}1}) and low temperatures (about 50{degrees}C) showed embrittlement more rapidly than expected. Commercial power reactors have similar flux levels and temperatures at the level vessel support structures. The purposes of this work are to provide the neutron fluence spectra data that are needed to evaluate previously measured mechanical property changes in the HFIR, to explain the discrepancies in neutron flux levels between the nickel dosimeters and two other dosimeters, neptunium and beryllium, and to address any questions or peculiarities of the HFIR reactor environment. The current work consists of neutron and gamma transport calculations, dosimetry measurements, and least-squares logarithmic adjustment to obtain the best estimates for the neutron spectra and the related neutron exposure parameters. The results indicate that the fission rates in neptunium-237 (Np-237) and uranium-238 (U-238) and the helium production rates in beryllium-9 (Be-9) are dominated by photo-induced reactions. The displacements per atom rate for iron (dpa/s) from gamma rays is five times higher than the dpa/s from neutrons. The neutron fluxes in key 7, position 5 do not show any significant gradient in the surveillance capsule, but key 4 and key 2 showed differences in magnitude as well as in the shape of the spectrum. The stainless steel monitor in the V-notch of the Charpy specimens of the surveillance capsules is adequate to determine the neutron flux above 1.0 MeV at the desired V-notch location. Simultaneous adjustment of neutron and gamma fluxes with the measurements has been demonstrated and should avoid future problems with photo-induced reactions.

  20. Asteroid Impact Monitoring

    Science.gov (United States)

    Milani, A.

    2006-06-01

    Some asteroids and comets with Earth-crossing orbit may impact our planet, thus we need to be able to identify the cases which could have a dangerous close approach within a century. This must be done as soon as such an asteroid is discovered, allowing for follow up observations which might contradict the impact possibility, and in the worst case to organize mitigation, possibly including deflection. The mathematical problem of predicting possible impacts, even with very low probabilities, has been solved by our group in the last few years. This paper presents the basic theory of these impact prediction, and discusses how they are practically used in the impact monitoring systems now operational, in particular the CLOMON2 robot of the Universities of Pisa and Valladolid.

  1. From Pressures to Impacts

    DEFF Research Database (Denmark)

    Hauschild, Michael Zwicky

    2006-01-01

    Life cycle assessment (LCA) has been developed as a tool for assessment of the environmental impacts which are caused by the pressures from products or systems, viewed in a life cycle perspective, i.e. covering all stages of the life cycle of the product or system from the extraction of raw...... is defined, Inventory analysis where data for the physical flows to and from all processes in the life cycle is collected and related to the functional unit, Impact assessment, where the physical flows are translated into impacts on the environment and resource base, and Interpretation where the outcomes...... of the earlier phases are interpreted in relation to the goal of the LCA. LCA is typically used for comparisons, and in order to facilitate the comparison of the rather diverse environmental impacts which are comprised by the Life Cycle Impact Assessment (LCIA) methodology, procedures have been developed...

  2. Integrated impact assessment

    Energy Technology Data Exchange (ETDEWEB)

    Porter, A.L.; Rossini, F.A.

    1981-12-01

    Impact assessment studies the effects on society of proposed projects, programs, or policies. It is perhaps best known in the forms of technology assessment and environmental-impact assessment. The institutionalization of impact assessment, the principal features of impact assessment and its performance are discussed here, keynoting interdisciplinarity as a critical factor. Substantial progress in performance has occurred over the past decade, especially in environmental and social analyses, pointing to some critical issues for the decade ahead. Within studies, integration across disciplinary components, between contributions from professionals and parties-at-interest, and between producers and users must be improved. Across studies, practitioners of impact assessment need to intercommunicate to advance the state of their art. 38 references.

  3. Climate Impacts on Human Health

    Science.gov (United States)

    ... Climate Change Impacts Human Health Impacts Human Health Climate Impacts on Human Health Climate Impacts on Alaska On This Page Temperature-Related ... very old) are especially vulnerable to health impacts. Climate Change Affects Human Health In 2016, the U.S. ...

  4. Environmental impact report (draft)

    Energy Technology Data Exchange (ETDEWEB)

    1980-05-01

    The three projects as proposed by Pacific Gas and Electric Company and the environmental analysis of the projects are discussed. Sections on the natural and social environments of the proposed projects and their surrounding areas consist of descriptions of the setting, discussions of the adverse and beneficial consequences of the project, and potential mitigation measures to reduce the effects of adverse impacts. The Environmental Impact Report includes discussions of unavoidable adverse effects, irreversible changes, long-term and cumulative impacts, growth-inducing effects, and feasible alternatives to the project. (MHR)

  5. Emotional impact of halitosis

    Directory of Open Access Journals (Sweden)

    Bernard Troger

    2014-12-01

    Full Text Available OBJECTIVE: To evaluate the emotional impact of halitosis on 18-year-old men using a self-reported questionnaire.METHOD:A total of 2,224 participants underwent dental and medical examinations in the army medical services in the city of Pelotas, southern Brazil, in July 2008.RESULTS: In this sample, 12% of respondents expressed concern about their oral malodor, which had a strong emotional impact on their quality of life.CONCLUSIONS: The individuals reporting halitosis showed a higher degree of concern with their oral malodor. Low educational level and low income were associated with psychological impact and halitosis in this population.

  6. Writing for Impact

    DEFF Research Database (Denmark)

    Meier, Ninna

    2016-01-01

    Academic work may have impact in a variety of ways, depending on purpose, audience and field, but this is most likely to happen when your work resonates in meaningful ways with people. Ninna Meier encourages a more systematic investigation of the role of writing in achieving impact. Impact through...... writing means getting your readers to understand and remember your message and leave the reading experience changed. The challenge is to make what you write resonate with an audience’s reservoir of experiential knowledge. If the words do not connect to anything tangible, interest can be quickly lost....

  7. Impact Against Offshore Pipelines

    OpenAIRE

    Mogstad, Ivar; Asheim, Tom Inge

    2013-01-01

    In 2007 a pipe at the Kvitebjørn oil field was impacted by an anchor and dragged out of its position. After the accident it was decided safe to run production, but later a leakage was found and the production was shut down. This gave rise to a need for further knowledge of the residual strength of impacted pipes.This thesis is part of an ongoing research program and a continuation of previous works. In 2010, scaled pipes were initially impacted in the pendulum accelerator at SIM lab, before t...

  8. Impact of granular drops

    KAUST Repository

    Marston, J. O.

    2013-07-15

    We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

  9. Weather Radar Impact Zones

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent an inventory of the national impacts of wind turbine interference with NEXRAD radar stations. This inventory was developed by the NOAA Radar...

  10. Economic impacts study

    Energy Technology Data Exchange (ETDEWEB)

    Brunsen, W.; Worley, W.; Frost, E.

    1988-09-30

    This is a progress report on the first phase of a project to measure the economic impacts of a rapidly changing U.S. target base. The purpose of the first phase is to designate and test the macroeconomic impact analysis model. Criteria were established for a decision-support model. Additional criteria were defined for an interactive macroeconomic impact analysis model. After a review of several models, the Economic Impact Forecast System model of the U.S. Army Construction Research Laboratory was selected as the appropriate input-output tool that can address local and regional economic analysis. The model was applied to five test cases to demonstrate its utility and define possible revisions to meet project criteria. A plan for EIFS access was defined at three levels. Objectives and tasks for scenario refinement are proposed.

  11. Quality Measurement Impact Reports

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Secretary of the Department of Health and Human Services is required to assess the impact of consensus-endorsed quality and efficiency measures used in federal...

  12. Impact Management System

    Data.gov (United States)

    US Agency for International Development — IMS (developed w/Iraq mission) is a system for conducting quality portfolio impact analysis, linking projects to strategy through integration of context data. IMS...

  13. 78 FR 13082 - Draft Environmental Impact Report/Environmental Impact Statement/Environmental Impact Statement...

    Science.gov (United States)

    2013-02-26

    ... Bureau of Reclamation Draft Environmental Impact Report/Environmental Impact Statement/ Environmental...: The Bureau of Reclamation has made available for public review and comment the draft Environmental Impact Report/Environmental Impact Statement/Environmental Impact Statement (EIR/EIS/EIS) for the...

  14. Earthquake impact scale

    Science.gov (United States)

    Wald, D.J.; Jaiswal, K.S.; Marano, K.D.; Bausch, D.

    2011-01-01

    With the advent of the USGS prompt assessment of global earthquakes for response (PAGER) system, which rapidly assesses earthquake impacts, U.S. and international earthquake responders are reconsidering their automatic alert and activation levels and response procedures. To help facilitate rapid and appropriate earthquake response, an Earthquake Impact Scale (EIS) is proposed on the basis of two complementary criteria. On the basis of the estimated cost of damage, one is most suitable for domestic events; the other, on the basis of estimated ranges of fatalities, is generally more appropriate for global events, particularly in developing countries. Simple thresholds, derived from the systematic analysis of past earthquake impact and associated response levels, are quite effective in communicating predicted impact and response needed after an event through alerts of green (little or no impact), yellow (regional impact and response), orange (national-scale impact and response), and red (international response). Corresponding fatality thresholds for yellow, orange, and red alert levels are 1, 100, and 1,000, respectively. For damage impact, yellow, orange, and red thresholds are triggered by estimated losses reaching $1M, $100M, and $1B, respectively. The rationale for a dual approach to earthquake alerting stems from the recognition that relatively high fatalities, injuries, and homelessness predominate in countries in which local building practices typically lend themselves to high collapse and casualty rates, and these impacts lend to prioritization for international response. In contrast, financial and overall societal impacts often trigger the level of response in regions or countries in which prevalent earthquake resistant construction practices greatly reduce building collapse and resulting fatalities. Any newly devised alert, whether economic- or casualty-based, should be intuitive and consistent with established lexicons and procedures. Useful alerts should

  15. El Salvador - Rural Electrification (Impact)

    Data.gov (United States)

    Millenium Challenge Corporation — The impact evaluation seeks to determine the impact of electrification on the cost of energy, energy consumption, time allocation, and household income. Because the...

  16. Experimental impact crater morphology

    Science.gov (United States)

    Dufresne, A.; Poelchau, M. H.; Hoerth, T.; Schaefer, F.; Thoma, K.; Deutsch, A.; Kenkmann, T.

    2012-04-01

    The research group MEMIN (Multidisciplinary Experimental and Impact Modelling Research Network) is conducting impact experiments into porous sandstones, examining, among other parameters, the influence of target pore-space saturation with water, and projectile velocity, density and mass, on the cratering process. The high-velocity (2.5-7.8 km/s) impact experiments were carried out at the two-stage light-gas gun facilities of the Fraunhofer Institute EMI (Germany) using steel, iron meteorite (Campo del Cielo IAB), and aluminium projectiles with Seeberg Sandstone as targets. The primary objectives of this study within MEMIN are to provide detailed morphometric data of the experimental craters, and to identify trends and characteristics specific to a given impact parameter. Generally, all craters, regardless of impact conditions, have an inner depression within a highly fragile, white-coloured centre, an outer spallation (i.e. tensile failure) zone, and areas of arrested spallation (i.e. spall fragments that were not completely dislodged from the target) at the crater rim. Within this general morphological framework, distinct trends and differences in crater dimensions and morphological characteristics are identified. With increasing impact velocity, the volume of craters in dry targets increases by a factor of ~4 when doubling velocity. At identical impact conditions (steel projectiles, ~5km/s), craters in dry and wet sandstone targets differ significantly in that "wet" craters are up to 76% larger in volume, have depth-diameter ratios generally below 0.19 (whereas dry craters are almost consistently above this value) at significantly larger diameters, and their spallation zone morphologies show very different characteristics. In dry craters, the spall zone surfaces dip evenly at 10-20° towards the crater centre. In wet craters, on the other hand, they consist of slightly convex slopes of 10-35° adjacent to the inner depression, and of sub-horizontal tensile

  17. Impact between deformable bodies

    International Nuclear Information System (INIS)

    The bodies are represented by constant strain finite elements so that the element internal forces can most easily be calculated, especially after yielding has taken place when the stress and strain increments are related in accordance with the Prandtl-Reuss theory. In the case of axisymmetrical problems triangular axisymmetrical elements are used whose properties are approximately calculated by sampling at the centroid of the cross-section. The external applied forces arise from the impact and contact forces at the interfaces, and the inertia forces are obtained from lumped mass matrices. The equation of motion is solved by a central difference explicit scheme in small incremental time steps. This enables the stress propagation as well as the history of plastic deformation in the bodies to be traced throughout the duration of impact. The material law is idealised to be piecewise linear, with an initial elastic portion followed by one linear hardening segment. Perfect plasticity (zero hardening) can also be allowed. A simple procedure deals with the case of loading from an elastic initial state to a final plastic state in one time step. The program has been applied to the investigation of a number of axisymmetrical problems. The three dimensional version of the program is now being coded. Examples: impact of a falling fuel stringer in a storage tube; impact of a cylinder on a rigid boundary; supported circular plate loaded by uniformly distributed impulses; impact of a non-return valve in a pipe rupture; impact of a cylindrical fuel-waste flask; impact of a conical missile on a rigid surface. (orig./HP)

  18. The Asteroid Impact Mission

    Science.gov (United States)

    Carnelli, Ian; Galvez, Andres; Mellab, Karim

    2016-04-01

    The Asteroid Impact Mission (AIM) is a small and innovative mission of opportunity, currently under study at ESA, intending to demonstrate new technologies for future deep-space missions while addressing planetary defense objectives and performing for the first time detailed investigations of a binary asteroid system. It leverages on a unique opportunity provided by asteroid 65803 Didymos, set for an Earth close-encounter in October 2022, to achieve a fast mission return in only two years after launch in October/November 2020. AIM is also ESA's contribution to an international cooperation between ESA and NASA called Asteroid Impact Deflection Assessment (AIDA), consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the AIM rendezvous spacecraft. The primary goals of AIDA are to test our ability to perform a spacecraft impact on a near-Earth asteroid and to measure and characterize the deflection caused by the impact. The two mission components of AIDA, DART and AIM, are each independently valuable but when combined they provide a greatly increased scientific return. The DART hypervelocity impact on the secondary asteroid will alter the binary orbit period, which will also be measured by means of lightcurves observations from Earth-based telescopes. AIM instead will perform before and after detailed characterization shedding light on the dependence of the momentum transfer on the asteroid's bulk density, porosity, surface and internal properties. AIM will gather data describing the fragmentation and restructuring processes as well as the ejection of material, and relate them to parameters that can only be available from ground-based observations. Collisional events are of great importance in the formation and evolution of planetary systems, own Solar System and planetary rings. The AIDA scenario will provide a unique opportunity to observe a collision event directly in space, and simultaneously from ground-based optical and

  19. Impact on floating membranes

    CERN Document Server

    Vandenberghe, Nicolas

    2016-01-01

    When impacted by a rigid object, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. In the first place, a longitudinal wave front -- associated with in-plane deformation of the membrane and traveling at constant speed -- separates an outward stress free domain with a stretched but flat domain. Then, in the stretched domain a dispersive transverse wave travels at a wave speed that depends on the local stretching rate. We study the dynamics of this fluid-body system and we show that the wave dynamics is similar to the capillary waves that propagate at a liquid-gas interface but with a surface tension coefficient that depends on impact speed. We emphasize the role of the stretching in the membrane in the wave dynamics but also in the development of a buckling instability that give rise to radial wrinkles.

  20. Meteoroid Impacts on Spacecraft

    Science.gov (United States)

    Foschini, Luigi

    In the space age, information about the near-Earth environment is becoming more and more important, because of the potential danger to human exploration and use of space. In recent years there have been a number of in situ space experiments, such as LDEF and EURECA, that have demonstrated the threaths to satellites, space station, and astronauts from high-kinetic-energy impacts of meteoroids and space debris. Post-flight analyses of data from these satellites have revealed that, the catastrophic impact to be a rare event; however, the main danger comes from the impact-generated plasma, which can produce several types of electromagnetic interferences that can disturb or even destroy on-board electronics.

  1. Economic impact of refugees

    Science.gov (United States)

    Taylor, J. Edward; Filipski, Mateusz J.; Alloush, Mohamad; Gupta, Anubhab; Rojas Valdes, Ruben Irvin; Gonzalez-Estrada, Ernesto

    2016-01-01

    In 2015, the United Nations High Commission for Refugees accommodated over 15 million refugees, mostly in refugee camps in developing countries. The World Food Program provided these refugees with food aid, in cash or in kind. Refugees’ impacts on host countries are controversial and little understood. This unique study analyzes the economic impacts of refugees on host-country economies within a 10-km radius of three Congolese refugee camps in Rwanda. Simulations using Monte Carlo methods reveal that cash aid to refugees creates significant positive income spillovers to host-country businesses and households. An additional adult refugee receiving cash aid increases annual real income in the local economy by $205 to $253, significantly more than the $120–$126 in aid each refugee receives. Trade between the local economy and the rest of Rwanda increases by $49 to $55. The impacts are lower for in-kind food aid, a finding relevant to development aid generally. PMID:27325782

  2. Violent breaking wave impacts

    DEFF Research Database (Denmark)

    Bredmose, Henrik; Peregrine, D.H.; Bullock, G.N.

    2009-01-01

    When an ocean wave breaks against a steep-fronted breakwater, sea wall or a similar marine structure, its impact on the structure can be very violent. This paper describes the theoretical studies that, together with field and laboratory investigations, have been carried out in order to gain...... a better understanding of the processes involved. The wave's approach towards a structure is modelled with classical irrotational flow to obtain the different types of impact profiles that may or may not lead to air entrapment. The subsequent impact is modelled with a novel compressible-flow model...... for a homogeneous mixture of incompressible liquid and ideal gas. This enables a numerical description of both trapped air pockets and the propagation of pressure shock waves through the aerated water. An exact Riemann solver is developed to permit a finite-volume solution to the flow model with smallest possible...

  3. NASA Lunar Impact Monitoring

    Science.gov (United States)

    Suggs, Robert M.; Moser, D. E.

    2015-01-01

    The MSFC lunar impact monitoring program began in 2006 in support of environment definition for the Constellation (return to Moon) program. Work continued by the Meteoroid Environment Office after Constellation cancellation. Over 330 impacts have been recorded. A paper published in Icarus reported on the first 5 years of observations and 126 calibrated flashes. Icarus: http://www.sciencedirect.com/science/article/pii/S0019103514002243; ArXiv: http://arxiv.org/abs/1404.6458 A NASA Technical Memorandum on flash locations is in press

  4. Emotional impact of halitosis

    OpenAIRE

    Bernard Troger; Hiram Laranjeira de Almeida Jr; Rodrigo Pereira Duquia

    2014-01-01

    OBJECTIVE: To evaluate the emotional impact of halitosis on 18-year-old men using a self-reported questionnaire.METHOD:A total of 2,224 participants underwent dental and medical examinations in the army medical services in the city of Pelotas, southern Brazil, in July 2008.RESULTS: In this sample, 12% of respondents expressed concern about their oral malodor, which had a strong emotional impact on their quality of life.CONCLUSIONS: The individuals reporting halitosis showed a higher degree of...

  5. Economic impacts of climate change

    OpenAIRE

    Tol, Richard S.J.

    2015-01-01

    Climate change will probably have a limited impact on the economy and human welfare in the 21st century. The initial impacts of climate change may well be positive. In the long run, the negative impacts dominate the positive ones. Negative impacts will be substantially greater in poorer, hotter, and lower-lying countries. Poverty reduction complements greenhouse gas emissions reduction as a means to reduce climate change impacts. Climate change may affect the growth rate of the economy and ma...

  6. Organizational Impact of RAMS.

    Science.gov (United States)

    Staebler, Mel

    A series of observations is made regarding the potential impact of the Remotely Accessible Management System (RAMS) upon the administrative structure of the Pontiac, Michigan City School System. Nine major results of the district wide needs assessment are reported, and evidence is advanced to support the conclusion that modern educational…

  7. Environmental Impacts - Coastal Ecosystems

    NARCIS (Netherlands)

    Bakker, J.P.; Baas, Andreas C.W.; Bartholdy, Jesper; Jones, Laurence; Ruessink, B.G.; Temmerman, Stijn; van de Pol, Martijn

    2016-01-01

    This chapter examines the impacts of climate change on the natural coastal ecosystems in the North Sea region. These comprise sandy shores and dunes and salt marshes in estuaries and along the coast. The chapter starts by describing the characteristic geomorphological features of these systems and t

  8. Global protected area impacts.

    Science.gov (United States)

    Joppa, Lucas N; Pfaff, Alexander

    2011-06-01

    Protected areas (PAs) dominate conservation efforts. They will probably play a role in future climate policies too, as global payments may reward local reductions of loss of natural land cover. We estimate the impact of PAs on natural land cover within each of 147 countries by comparing outcomes inside PAs with outcomes outside. We use 'matching' (or 'apples to apples') for land characteristics to control for the fact that PAs very often are non-randomly distributed across their national landscapes. Protection tends towards land that, if unprotected, is less likely than average to be cleared. For 75 per cent of countries, we find protection does reduce conversion of natural land cover. However, for approximately 80 per cent of countries, our global results also confirm (following smaller-scale studies) that controlling for land characteristics reduces estimated impact by half or more. This shows the importance of controlling for at least a few key land characteristics. Further, we show that impacts vary considerably within a country (i.e. across a landscape): protection achieves less on lands far from roads, far from cities and on steeper slopes. Thus, while planners are, of course, constrained by other conservation priorities and costs, they could target higher impacts to earn more global payments for reduced deforestation.

  9. Making a global impact.

    Science.gov (United States)

    2015-12-12

    How can vets, individually and collectively, make an impact on the global stage? Addressing this question at the BVA Congress at the London Vet Show, René Carlson, president of the World Veterinary Association, encouraged the profession to play its part locally, nationally and internationally, in tackling current challenges. Kristy Ebanks reports. PMID:26667429

  10. Social Impact Assessment in Europe

    DEFF Research Database (Denmark)

    Larsen, Sanne Vammen; Hansen, Anne Merrild; Lyhne, Ivar;

    2015-01-01

    Social impact assessment (SIA) is applied worldwide to assess social impacts of plans and projects. In Europe, directives on environmental assessment (EA) require attention to social impacts, however, there is a need to investigate the implementation in practise. To this end, we study three Danish...... cases, which are characterised by debates and conflicts on social issues. Analysis of the EA statements shows inclusion of a broad range of social impacts. However, the EAs do not fully match the concerns of the public, and social impacts are not always analysed in depth, mitigation measures are not...... suggested or are postponed and the geographical distribution of impacts assessed is biased towards including negative local impacts. We discuss the scope and handling of social impacts, and possible implications. Based on this, we conclude with the view that EA might do the job of handling social impacts in...

  11. 76 FR 62442 - Final Environmental Impact Report/Environmental Impact Statement for Upper Truckee River...

    Science.gov (United States)

    2011-10-07

    ... Bureau of Reclamation Final Environmental Impact Report/Environmental Impact Statement for Upper Truckee.... ACTION: Notice of availability. SUMMARY: The final Environmental Impact Report/Environmental Impact... publication of the final Environmental Impact Report/Environmental Impact Statement. ADDRESSES: The...

  12. Reducing Impacts of Forestry

    DEFF Research Database (Denmark)

    Weidema, Bo Pedersen

    2013-01-01

    New definitions are provided of intensive and extensive forestry in version 3 of the ecoinvent database. These definitions are based on explicit and easily measured indicators for the most important aspects of forestry management for biodiversity. Unfortunately, many certified forestry products...... come from what would be classified as intensive forestry in the ecoinvent classification. The real challenge is to develop forest management systems that have a neutral or positive biodiversity impact relative to that of plantation forestry. Such truly extensive, biodiversity-managed forestry is very...... challenging and not very common today. Ample options exist for increasing yields in intensive and plantation forests, which can be recommended as having lower biodiversity impact than similar products from other management systems, certified or not....

  13. Pipe whip and impact

    International Nuclear Information System (INIS)

    Over the past few years changes in economic and safety considerations in nuclear power plants have resulted in a need to examine the problem of pipe whip in greater detail. Consequently, experimental programmes were set up in France, North America and Britain. Results from these tests combined with analytical work indicate that pipe whip followed by impact with surrounding pipework and structures may not be as serious as had been believed. Impact loads have been found to be much less (at least five times) than those predicted to the appropriate design regulations. Hence, the use of pipe whip restraints may have been overconservative. The use of fewer, better designed restraints, would result in greater accessibility of pipework, a reduced need for inspection of restraints, and a considerable financial saving. (author)

  14. The Cambrian impact hypothesis

    CERN Document Server

    Zhang, Weijia

    2008-01-01

    After a thorough research on the circumstantial changes and the great evolution of life in the Cambrian period, the author propounds such a hypothesis: During the Late Precambrian, about 500-600Ma, a celestial body impacted the Earth. The high temperature ended the great glaciation, facilitated the communication of biological information. The rapid change of Earth environment enkindled the genesis-control system, and released the HSP-90 variations. After the impact, benefited from the protection of the new ozone layer and the energy supplement of the aerobic respiration, those survived underground life exploded. They generated carapaces and complex metabolism to adjust to the new circumstance of high temperature and high pressure. This article uses a large amount of analyses and calculations, and illustrates that this hypothesis fits well with most of the important incidences in astronomic and geologic discoveries.

  15. Temperature profiles of impacts

    Energy Technology Data Exchange (ETDEWEB)

    Canavan, G.H.

    1997-05-01

    Similarity solutions determine the profiles of density and temperature from impacts, which determine the scaling of the temperature and optical depth on material parameters, time, screening, and impactor size. This note uses scaling results derived earlier for the growth, size, and temperature produced by impacts to discuss the radial temperature profiles they produce. While the plasmas cool in milliseconds, they offer unique information about the thermodynamic state and material properties of the target material. The brightness temperature can be estimated from known two-dimensional similarity solutions. Regions close to unit optical thickness contribute effectively to the radiation, hence, they determine the plasma brightness temperature. The estimates of temperature as a function of time can be combined with the estimates of the exit hole size to estimate the total observable signal, which should be readily observable from distances of hundreds of kilometers.

  16. Project X Broader Impacts

    CERN Document Server

    Asner, D M; Henderson, S; Plunkett, R; Wootan, D W; Peterson, M A; Senor, D; Tschirhart, R; Grasselino, A; Romanenko, A; MacDougall, G; Heffner, R H

    2013-01-01

    Part-3 of "Project X: Accelerator Reference Design, Physics Opportunities, Broader Impacts". The proposed Project X proton accelerator at Fermilab, with multi-MW beam power and highly versatile beam formatting, will be a unique world-class facility to explore particle physics at the intensity frontier. Concurrently, however, it can also facilitate important scientific research beyond traditional particle physics and provide unprecedented opportunities in applications to problems of great national importance in the nuclear energy and security sector.

  17. Impact craters on Titan

    Science.gov (United States)

    Wood, Charles A.; Lorenz, Ralph; Kirk, Randy; Lopes, Rosaly; Mitchell, Karl; Stofan, Ellen; ,

    2010-01-01

    Five certain impact craters and 44 additional nearly certain and probable ones have been identified on the 22% of Titan's surface imaged by Cassini's high-resolution radar through December 2007. The certain craters have morphologies similar to impact craters on rocky planets, as well as two with radar bright, jagged rims. The less certain craters often appear to be eroded versions of the certain ones. Titan's craters are modified by a variety of processes including fluvial erosion, mass wasting, burial by dunes and submergence in seas, but there is no compelling evidence of isostatic adjustments as on other icy moons, nor draping by thick atmospheric deposits. The paucity of craters implies that Titan's surface is quite young, but the modeled age depends on which published crater production rate is assumed. Using the model of Artemieva and Lunine (2005) suggests that craters with diameters smaller than about 35 km are younger than 200 million years old, and larger craters are older. Craters are not distributed uniformly; Xanadu has a crater density 2-9 times greater than the rest of Titan, and the density on equatorial dune areas is much lower than average. There is a small excess of craters on the leading hemisphere, and craters are deficient in the north polar region compared to the rest of the world. The youthful age of Titan overall, and the various erosional states of its likely impact craters, demonstrate that dynamic processes have destroyed most of the early history of the moon, and that multiple processes continue to strongly modify its surface. The existence of 24 possible impact craters with diameters less than 20 km appears consistent with the Ivanov, Basilevsky and Neukum (1997) model of the effectiveness of Titan's atmosphere in destroying most but not all small projectiles.

  18. Towards enhanced CSR impact?

    International Nuclear Information System (INIS)

    This paper was produced by ECON Analysis in conjunction with the Fridtjof Nansen Institute (FNI) for the Norwegian Research Council's 'Petropol' programme. It is part of a joint project entitled, 'Oil companies and the new petroleum provinces: ethics, business and politics'. This paper examines the possibilities for partnerships between oil companies and multilateral government institutions to address the negative impacts of oil projects that often prevent the resulting revenues leading to social and economic benefits for the host country (author) (ml)

  19. Novel Research Impact Indicators

    OpenAIRE

    Martin Fenner; Jennifer Lin

    2014-01-01

    Citation counts and more recently usage statistics provide valuable information about the attention and research impact associated with scholarly publications. The open access publisher Public Library of Science (PLOS) has pioneered the concept of article-level metrics, where these metrics are collected on a per article and not a per journal basis and are complemented by real-time data from the social web or altmetrics: blog posts, social bookmarks, social media and other.

  20. Milestones and Impact Factors

    Directory of Open Access Journals (Sweden)

    Grandjean Philippe

    2010-07-01

    Full Text Available Abstract Environmental Health has just received its first Impact Factor by Thomson ISI. At a level of 2.48, this achievement is quite satisfactory and places Environmental Health in the top 25% of environmental science journals. When the journal was launched in 2002, it was still unclear whether the Open Access publishing model could be made into a viable commercial enterprise within the biomedical field. During the past eight years, Open Access journals have become widely available, although still covering only about 15% of journal titles. Major funding agencies and institutions, including prominent US universities, now require that researchers publish in Open Access journals. Because of the profound role of scientific journals for the sharing of results and communication between researchers, the advent of Open Access may be of as much significance as the transition from handwriting to printing via moveable type. As Environmental Health is an electronic Open Access journal, the numbers of downloads at the journal website can be retrieved. The top-20 list of articles most frequently accessed shows that all of them have been downloaded over 10,000 times. Back in 2002, the first article published was accessed only 49 times during the following month. A year later, the server had over 1,000 downloads per month, and now the total number of monthly downloads approaches 50,000. These statistics complement the Impact Factor and confirm the viability of Open Access in our field of research. The advent of digital media and its decentralized mode of distribution - the internet - have dramatically changed the control and financing of scientific information dissemination, while facilitating peer review, accelerating editorial handling, and supporting much needed transparency. Both the meaning and means of "having an impact" are therefore changing, as will the degree and way in which scientific journals remain "factors" in that impact.

  1. Demonstration project as a procedure for accelerating the application of new technology (Charpie Task Force report). Volume II

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-02-01

    This report examines the issues associated with government programs proposed for the ''commercialization'' of new energy technologies; these programs are intended to hasten the pace at which target technologies are adopted by the private sector. The ''commercial demonstration'' is the principal tool used in these programs. Most previous government interventions in support of technological change have focused on R and D and left to the private sector the decision as to adoption for commercial utilization; thus there is relatively little in the way of analysis or experience which bears direct application. The analysis is divided into four sections. First, the role of R, D, and D within the structure of the national energy goals and policies is examined. The issue of ''prices versus gaps'' is described as a crucial difference of viewpoint concerning the role of the government in the future of the energy system. Second, the process of technological change as it occurs with respect to energy technologies is then examined for possible sources of misalignment of social and private incentives. The process is described as a series of investments. Third, correction of these sources of misalignment then becomes the goal of commercial demonstration programs as this goal and the means for attaining it are explored. Government-supported commercialization may be viewed as a subsidy to the introduction stage of the process; the circumstances under which such subsidies are likely to affect the success of the subsequent diffusion stage are addressed. The discussion then turns to the political, legal, and institutional problems. Finally, methods for evaluation and planning of commercial demonstration programs are analyzed. The critical areas of ignorance are highlighted and comprise a research agenda for improved analytical techniques to support decisions in this area.

  2. The IMPACT clinic

    Science.gov (United States)

    Tracy, C. Shawn; Bell, Stephanie H.; Nickell, Leslie A.; Charles, Jocelyn; Upshur, Ross E.G.

    2013-01-01

    Abstract Problem addressed The growing number of elderly patients with multiple chronic conditions presents an urgent challenge in primary care. Current practice models are not well suited to addressing the complex health care needs of this patient population. Objective of program The primary objective of the IMPACT (Interprofessional Model of Practice for Aging and Complex Treatments) clinic was to design and evaluate a new interprofessional model of care for community-dwelling seniors with complex health care needs. A secondary objective was to explore the potential of this new model as an interprofessional training opportunity. Program description The IMPACT clinic is an innovative new model of interprofessional primary care for elderly patients with complex health care needs. The comprehensive team comprises family physicians, a community nurse, a pharmacist, a physiotherapist, an occupational therapist, a dietitian, and a community social worker. The model is designed to accommodate trainees from each discipline. Patient appointments are 1.5 to 2 hours in length, during which time a diverse range of medical, functional, and psychosocial issues are investigated by the full interprofessional team. Conclusion The IMPACT model is congruent with ongoing policy initiatives in primary care reform and enhanced community-based care for seniors. The clinic has been pilot-tested in 1 family practice unit and modeled at 3 other sites with positive feedback from patients and families, clinicians, and trainees. Evaluation data indicate that interprofessional primary care models hold great promise for the growing challenge of managing complex chronic disease. PMID:23486816

  3. Carbonaceous Survivability on Impact

    Science.gov (United States)

    Bunch, T. E.; Becker, Luann; Morrison, David (Technical Monitor)

    1994-01-01

    In order to gain knowledge about the potential contributions of comets and cosmic dust to the origin of life on Earth, we need to explore the survivability of their potential organic compounds on impact and the formation of secondary products that may have arisen from the chaotic events sustained by the carriers as they fell to Earth. We have performed a series of hypervelocity impact experiments using carbon-bearing impactors (diamond, graphite, kerogens, PAH crystals, and Murchison and Nogoya meteorites) into Al plate targets at velocities - 6 km/s. Estimated peak shock pressures probably did not exceed 120 GPa and peak shock temperatures were probably less than 4000 K for times of nano- to microsecs. Nominal crater dia. are less than one mm. The most significant results of these experiments are the preservation of the higher mass PAHs (e. g., pyrene relative to napthalene) and the formation of additional alkylated PAHs. We have also examined the residues of polystyrene projectiles impacted by a microparticle accelerator into targets at velocities up to 15 km/s. This talk will discuss the results of these experiments and their implications with respect to the survival of carbonaceous deliverables to early Earth. The prospects of survivability of organic molecules on "intact" capture of cosmic dust in space via soft: and hard cosmic dust collectors will also be discussed.

  4. Environmental impacts program

    International Nuclear Information System (INIS)

    The Environmental Impacts Program (EIP) prepared environmental analyses relating to federal energy planning and decision-making processes. This effort includes preparation of Environmental Impact Statements (EISs) and Environmental Assessments (EIAs), development of environmental monitoring strategies and protocols, formulation of guidelines and environmental compliance documents, and technical assistance. The Program assists the Department of Energy (D0E) and the Nuclear Regulatory Commission (NRC) in accomplishing their environmental responsibilities under the National Environmental Policy Act (NEPA). The EIP is organized around six team activities: Power Stations, Nuclear Fuel Cycle, Geothermal Energy and Fuel Conversions, NEPA Affairs and Fossil Energy, Monitoring Protocols Development, and Solar and Special Projects. Impact statement work is a cooperative effort with the ORNL Energy Division, in which the EIP analyzes issues dealing with terrestrial and aquatic ecology and land and water use. The primary goal of the Program is to promote the inclusion of scientifically sound and supportable environmental analyses and advice as input into major federal decisions. To implement this goal the EIP engaged in several activities this year which provide guidance, technical assistance, planning, and long-range analyses

  5. Aluminum alloy impact sparkling

    Directory of Open Access Journals (Sweden)

    M. Dudyk

    2008-08-01

    Full Text Available The cast machine parts are widely used in many branches of industry. A very important issue is gaining the appropriate knowledge relating to the application of castings in places of explosion risks including but not limited to mining, chemical industry and rescue works. A possibility of explosion risks occurrence following the impact sparkling of the cast metal parts is still not solved problem in scientific research. In relation to this issue, in this article, the results of the study are presented, and relating to the tendency to impact sparkling of the aluminium alloys used in machine building. On the grounds of the results obtained, it was demonstrated that the registered impact sparkles bunches of feathers from the analyzed alloys: AlSi7Mg, (AK7; AlSi9Mg, (AK9; AlSi6Cu4, (AK64 and AlSi11, (AK11 show significant differences between each other. The quantitative analysis of the temperature distribution and nuclei surface area performed on the example of the alloy AK9 (subjected to defined period of corrosion allows for the statement that they are dangerous in conditions of explosion risk. Following this fact, designers and users of machine parts made from these materials should not use them in conditions where the explosive mixtures occur.

  6. Environmental Impact Section

    International Nuclear Information System (INIS)

    The Section is concerned with preparation of environmental statements and assessments and development of assessment methodologies for energy technologies. During 1976, activities involved nuclear, fossil, and geothermal energy; this work was supported by the U.S.Army, HUD, US ERDA, and US NRC. Two special studies--one on the effects of power plant intake structures on fish impingement and another on multiple uses of cooling lakes--were completed and should serve as references for future analyses. Two research projects sponsored by NRC--the Unified Transport Approach (UTA) to Power Plant Assessment and the Environmental Monitoring Data Evaluation Study--were continued. The purpose of the UA program is to develop fast-transient, one- and two-dimensional transport models for estimating thermal, radiological, chemical, and biological impacts in complicated water bodies. The impact of public use of various products that contain radioactive isotope is being evaluated. The Environmental Impact Sections assistance to NRC expanded to include assessments of fuel-fabrication facilities being considered for relicensing and two uranium in-situ solution mining facility proposals. The work for HUD comprises an assessment of the first application of MIUS in a new town development. A generic environmental statement was prepared and an environmental monitoring program for the facility was designed

  7. Tornado missile impact study

    International Nuclear Information System (INIS)

    UCRL-15910 specifies wind and tornado missiles for moderate- and high-hazard DOE facilities. Wall-barrier specimens have been tested at the Tornado Missile Impact Facility at Texas Tech University. The facility has an air-activated tornado missile cannon capable of firing 2x4 timber planks weighing 12 lb at speeds up to 150 mph and 3-in-diameter steel pipes weighing 75 lb at speeds to 7 5 mph. Wall barriers tested to date include reinforced concrete walls from 4-in. to 10-in. thick; 8-in. and 12-in. walls of reinforced concrete masonry units (CMU); two other masonry wall configurations consisting of an 8-in. CMU with a 4-in. clay-brick veneer and a 10-in. composite wall with two wythes of 4-in. clay brick. The impact test series is designed to determine the impact speed that will produce backface spall of each wall barrier. A set of 15 wall sections has been constructed and tested at this time. Preliminary finding suggest that all cells of CMU walls must be grouted to prevent missile penetration. Walls recommended in the workshop on UCRL-15910 provide acceptable protection if cracking can be accepted

  8. Ecotoxicology & Impact on Biodiversity

    Directory of Open Access Journals (Sweden)

    Shanky Bhat

    2013-07-01

    Full Text Available Ecotoxicology can be defined as the ‘study of impacts of pollutants on the structure and function of ecosystems’ it can be by manmade poisonous chemicals and their effect on the environment, it does not include the study of naturally occurring toxins or it is a scientific discipline combining the methods of ecology and toxicology in studying the effects of toxic substances and especially pollutants on the environment. Ecotoxicology is a mix of various discipline ecology, toxicology, analytical chemistry, physiology, molecular biology, and mathematics. Ecotoxicology looks at the impacts of contaminants including populations, pesticides on individuals, natural communities, and ecosystems. Communities of living things and the environments they live in form ecosystems.Ecosystems include rivers, ponds, deserts, grasslands, and forests, and they too can be affected by pesticides. Ecotoxicologists also study what happens to the pesticides themselves, where they go in the environment, how long they last, and how they finally break down. Herein we review what is ecotoxicology, different kinds of toxicants their impact on biodiversity, assessment of toxicity of environmental toxicant.

  9. Preparing for the Impact

    Science.gov (United States)

    2005-05-01

    On July 4, 2005, the NASA Deep Impact spacecraft will visit Comet 9P/Tempel 1. It will launch a 360 kg impactor that should produce a crater on the surface of the comet and a plume of gas and dust. This experiment will be the first opportunity to study the crust and the interior of a comet. As the material inside the comet's nucleus is pristine, it will reveal new information on the early phases of the Solar System. It will also provide scientists with new insight on crater physics, and thereby give a better understanding on the crater record on comets and other bodies in the Solar System. The scientific outcome of the experiment depends crucially on pre-impact and follow-up observations. Before the impact, it is indeed necessary to accumulate a significant amount of data so as to fully characterise the comet, in terms of size, albedo (reflectivity), rotation period, etc. It is also essential to have a good baseline of observations before the impact to unambiguously discriminate the effects of the impact from the natural activity of the comet. Due to the currently limited understanding of the structure of these dirty snowballs - which is a rather precise definition of a comet - it is indeed far from clear what the effect of the impact will be. Although the most likely model predicts the ejection of a plume and a football stadium sized crater, other model predictions vary between the comet simply swallowing the impactor (with barely any visible effect) to the eventual break-up of the nucleus. As part of a very large international collaboration, two teams of astronomers have used ESO's telescopes over several months to do pre-impact monitoring, taking images and spectra of the comet both in the visible and mid-infrared wavebands. These teams make observations typically once per month, using either the 3.6m or the 3.5m NTT telescopes at La Silla. ESO PR Photo 17/05 shows the latest of these monitoring images. Obtained during the night of May 4 to 5 with the EMMI

  10. Methodology for Environmental Impact Assessment

    International Nuclear Information System (INIS)

    This report is an appendix to 'Environmental Impact Assessment Interim storage, encapsulation and disposal of spent nuclear fuel'. The appendix presents the methodology and criteria used in support investigations to conduct impact assessments

  11. Measuring impact in research evaluations

    CERN Document Server

    Bornmann, Lutz

    2014-01-01

    Governments all over the world are contemplating the question of where they should distribute public money (to education or to defence, for example). Distribution of money over a number of different areas always makes an issue, implicitly or explicitly, of the impact which can be achieved with investment in any one of them. Science is also affected by this governmental interest in impact; the issue is not only the impact of research on research itself, but on other areas of society. Citations are traditionally used to measure the impact of research on research. It is as yet unclear how the impact of research on other areas of society can be measured. It appears that alternative metrics (altmetrics, such as Twitter counts) might play a key role in this. This paper is concerned with the measurement of citation impact and societal impact, and looks at the basis, the effects and the problems of impact measurement.

  12. Impacted Teeth and Mandibular Fracture

    OpenAIRE

    Metin, Murat; Şener, İsmail; Tek, Mustafa

    2007-01-01

    Objectives In this retrospective study, we measured the relationship between the presences of impacted or unerupted teeth in the mandible and mandibular fractures. Methods The records and radiographs of 41 patients with mandibular fracture associated with impacted or unerupted teeth were examined. The presence of impacted or unerupted teeth were assessed for each patient and related to the occurrence of fractures of mandible. Results Patients with fracture in the impacted or unerupted teeth a...

  13. Investigation on the Full Thickness Repair Welding Process of X80Mφ1 219 mm×18.4 mm SAWH Pipe%X80M级准1219 mm×18.4 mm螺旋埋弧焊管全壁厚补焊工艺研究

    Institute of Scientific and Technical Information of China (English)

    杨军; 苟世峰; 符利兵; 陈长青

    2015-01-01

    利用夏比冲击、显微硬度和拉伸试验对6种焊材在相同补焊工艺下的全壁厚刨透补焊焊缝进行了性能对比研究,筛选出焊缝性能较优的对应补焊焊材。并以此焊材作为X80M级φ1219 mm ×18.4 mm螺旋埋弧焊管焊缝缺陷手工修补用专用焊材,进行了不同补焊工艺参数的全壁厚刨透补焊试验,并对补焊焊缝进行低温冲击试验,通过比较确定出X80M级φ1219 mm×18.4 mm螺旋埋弧焊管全壁厚刨透补焊工艺方案。结果表明,上海焊接器材厂生产的SH J557焊条用于X80M级φ1219 mm×18.4 mm螺旋埋弧焊管焊缝缺陷全壁厚刨透手工修补更为合适,各项性能指标更高;确定的补焊工艺参数合理可行,确保了补焊焊缝的质量和钢管的批量化生产。%The properties of full thickness repair welding seam that generated by 6 kinds of welding material under the same repair welding condition were comparatively investigated by V-notch Charpy impact toughness test, micro-hardness test and tensile test, and selected out the repair welding material matching with better weld performance. Taking the selected welding material as special welding material for manual repairing the weld defect in φ1 219 mm ×18.4 mm X80M SAWH pipe, the full thickness repair welding tests for the different welding process parameter were conducted, and the low temperature impact test for repair weld was carried out. Finally, it determined the repair welding process for φ1 219 mm×18.4 mm X80M SAWH pipe. The results indicated that the SHJ557 welding electrode produced by Shanghai Welding Equipment Factory is more suitable for the above repair welding process of φ1 219 mm ×18.4 mm X80M SAWH pipe, the various performance indexes are higher; the determined repair welding process parameters are reasonable, it ensures the quality of repair weld and the mass production of steel pipe.

  14. Monitoring gender impacts of trade

    NARCIS (Netherlands)

    I.P. van Staveren (Irene)

    2003-01-01

    textabstractIn the light of increased attention to trade impacts on labour conditions, poverty, and the environment, this article focuses on trade impacts on gender [in]equality. Gender impacts of trade have received hardly any attention so far from policy-makers. At the same time, however, gender e

  15. Post mortem investigations of the NPP Greifswald WWER-440 reactor pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Viehrig, H.W.; Rindelhardt, U.; Schuhknecht, J. [Forschungszentrum Dresden-Rossendorf e.V., Inst. for Safety Research, Dresden (Germany)

    2007-07-01

    The paper presents first results of the post mortem investigations performed on the reactor pressure vessels (RPV) of the Russian WWER-440 type reactors. Trepans were taken from the core weld SN0.1.4 and base metal of the unit 1 RPV. This RPV was annealed after 15 years of operation and operated for two more years. At first the trepan of the core welding seam was investigated by Master Curve (MC) and Charpy V-notch testing. Specimens from 5 locations through the thickness of the welding seam were tested according to ASTM E1921-05. The reference temperature T{sub 0} was calculated with the measured fracture toughness values, K{sub Jc}, at brittle failure of the specime. Generally the K{sub Jc} values measured on pre-cracked and side-grooved Charpy size SE(B) specimens of the investigated weld metal follows the course of the Master Curve. The K{sub Jc} values show a remarkable scatter. More values than expected lie below the 5% fractile. In addition the MC SINTAP procedure was applied to determine T{sub 0}{sup SINTAP} of the brittle fraction of the data set. There are remarkable differences between T{sub 0} and T{sub 0}{sup SINTAP} indicating macroscopic inhomogeneous weld metal. The highest T{sub 0} was about 50 C at a distance of 22 mm from the inner surface of the weld. It is 40 K higher compared with T{sub 0} at the inner surface. This is important for the assessment of ductile-to-brittle temperatures measured with sub size. (orig.)

  16. Application of small specimens to fracture mechanics characterization of irradiated pressure vessel steels

    International Nuclear Information System (INIS)

    In this study, precracked Charpy V-notch (PCVN) specimens were used to characterize the fracture toughness of unirradiated and irradiated reactor pressure vessel steels in the transition region by means of three-point static bending. Fracture toughness at cleavage instability was calculated in terms of elastic-plastic KJc values. A statistical size correction based upon weakest-link theory was performed. The concept of a master curve was applied to analyze fracture toughness properties. Initially, size-corrected PCVN data from A 533 grade B steel, designated HSST Plate O2, were used to position the master curve and a 5% tolerance bound for KJc data. By converting PCVN data to IT compact specimen equivalent KJc data, the same master curve and 5% tolerance bound curve were plotted against the Electric Power Research Institute valid linear-elastic KJc database and the ASME lower bound KIc curve. Comparison shows that the master curve positioned by testing several PCVN specimens describes very well the massive fracture toughness database of large specimens. These results give strong support to the validity of KJc with respect to KIc in general and to the applicability of PCVN specimens to measure fracture toughness of reactor vessel steels in particular. Finally, irradiated PCVN specimens of other materials were tested, and the results are compared to compact specimen data. The current results show that PCVNs demonstrate very good capacity for fracture toughness characterization of reactor pressure vessel steels. It provides an opportunity for direct measurement of fracture toughness of irradiated materials by means of precracking and testing Charpy specimens from surveillance capsules. However, size limits based on constraint theory restrict the operational test temperature range for KJc data from PCVN specimens. 13 refs., 8 figs., 1 tab

  17. Efeito do tratamento térmico de envelhecimento na microestrutura e nas propriedades de impacto do aço inoxidável superaustenítico ASTM A 744 Gr. CN3MN Aging heat treatment effect on the microstructure and impact properties of the super-austenitic stainless steel ASTM A 744 Gr. CN3MN

    Directory of Open Access Journals (Sweden)

    Márcio Ritoni

    2010-03-01

    Full Text Available O aço inoxidável superaustenítico ASTM A 744 Gr. CN3MN é aplicado na fabricação de equipamentos que trabalham em ambientes sob corrosão severa com solicitação mecânica. Nesse trabalho, investigou-se a influência do tratamento térmico de envelhecimento na microestrutura e nas propriedades de impacto desse tipo de material. Foram realizados tratamentos térmicos de envelhecimento a 900°C por 1,5; 12; 24; 36 e 48 horas. Ensaios de impacto na temperatura ambiente e a -46°C foram realizados nas amostras tratadas termicamente. As análises microestruturais foram feitas por meio de microscopia eletrônica de varredura e difração de raios X. Concluiu-se que quanto maior a o tempo de exposição do material à temperatura de 900°C, menor é a energia absorvida no impacto. Com 1,5 horas o material apresentou redução na resistência ao impacto de 128 para 25 Joules. O tratamento térmico a 900°C por 48 horas causou a precipitação de algumas fases na matriz austenítica, sendo as mais prováveis: sigma (σ, chi (χ e carboneto M23C6.ASTM A 744 Gr. CN3MN superaustenitic stainless steel is employed in the manufacture of equipments designed to work in severely corrosive environments under mechanical loads. This research investigated the influence of aging heat treatments on the microstructure and impact properties of this type of material. These treatments were carried out at temperature of 900ºC for different periods of time: 1.5; 12; 24; 36 and 48 hours. Impact Charpy tests were conducted at room temperature and -46°C for all heat treated samples. The microstructural analyses were carried out by optical microscopy, scanning electron microscopy and X-ray diffraction. It was concluded that as long as the steel was exposed to 900ºC, the energy absorbed during impact was lower. After 1.5 hours at 900ºC the impact energy dropped from 128 to 25 Joules. The samples heat treated at 900ºC for 48 hours showed precipitation of some phases at

  18. Social Impact, a Theoretical Model

    Directory of Open Access Journals (Sweden)

    Jenny Onyx

    2014-01-01

    Full Text Available This paper constructs a theoretical model of social impact as it applies to civil society organisations. It does so by drawing on the recent literature on the topic as well as recently completed empirical studies. First, the relationship between impact and evaluation is examined. This is followed by an exploration of the capitals, notably social, human, and cultural capital and their interrelationships, as a theoretical base for the explication of social impact. A formal model of social impact is then identified together with a set of basic principles that may be said to define social impact. Finally the implications of the model are discussed for social policy and organisational management.

  19. IMPACT fragmentation model developments

    Science.gov (United States)

    Sorge, Marlon E.; Mains, Deanna L.

    2016-09-01

    The IMPACT fragmentation model has been used by The Aerospace Corporation for more than 25 years to analyze orbital altitude explosions and hypervelocity collisions. The model is semi-empirical, combining mass, energy and momentum conservation laws with empirically derived relationships for fragment characteristics such as number, mass, area-to-mass ratio, and spreading velocity as well as event energy distribution. Model results are used for several types of analysis including assessment of short-term risks to satellites from orbital altitude fragmentations, prediction of the long-term evolution of the orbital debris environment and forensic assessments of breakup events. A new version of IMPACT, version 6, has been completed and incorporates a number of advancements enabled by a multi-year long effort to characterize more than 11,000 debris fragments from more than three dozen historical on-orbit breakup events. These events involved a wide range of causes, energies, and fragmenting objects. Special focus was placed on the explosion model, as the majority of events examined were explosions. Revisions were made to the mass distribution used for explosion events, increasing the number of smaller fragments generated. The algorithm for modeling upper stage large fragment generation was updated. A momentum conserving asymmetric spreading velocity distribution algorithm was implemented to better represent sub-catastrophic events. An approach was developed for modeling sub-catastrophic explosions, those where the majority of the parent object remains intact, based on estimated event energy. Finally, significant modifications were made to the area-to-mass ratio distribution to incorporate the tendencies of different materials to fragment into different shapes. This ability enabled better matches between the observed area-to-mass ratios and those generated by the model. It also opened up additional possibilities for post-event analysis of breakups. The paper will discuss

  20. Impacts of March 11

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Feng: The world-shocking September 11 terrorist attacks occurred in the United States in 2001, and two and a half years late the world saw panic-stricken terrorist attacks of the same kind in Spain. Ever since then March 11 has become another day that is engraved on the mind of the people all over the world. The terrorist event in Madrid has not only produced great impact on Spain and other European nations as well as on the common people, but also spurred the European nations to reflect on a series of important issues and to make some adjustments of their policies.

  1. Environment and environmental impacts

    Directory of Open Access Journals (Sweden)

    Rejane de Fátima Victor Vasconcelos

    2009-12-01

    Full Text Available The article shows what can be environmental impacts and how those happen, both by the actions made by human kind and by natural disasters. Another concern of the research is the unstoppable incident of the natural resources destruction, result f the globalization actions and the economy, and that the environment impacts have happen in every direction, independently of the geographic scale, harming the life in earth, without giving importance who is the target. The article made reference to incidents because of the disorder of the environment, the consequences of rural exodus, the improper tourism, and which actions to solve this problem have not been enough. With reference to sustainable development, it is waited that everyone can live under environmental, social and economical equilibrium, and also has reasonable habit, being sensible to the conservation of the environmental practice. The article emphasizes the values as a need in the equilibrium of sustainability, and even made reference to the lost of the country in the sustainable development and that Brazil could have more interest by the cause, mainly in the managing in the use of pesticides e fungicides in agriculture. The concern with the globalized economy is a radical change which the developing countries are facing. The cause affects of pollutions resulting in health problems. The danger that humanity faces with its own action, as predatory fishing, causing aquatic disorder and the invasion of commerce in the area of permanent conservation.

  2. Landscapes Impacted by Light

    Science.gov (United States)

    Arellano, B.; Roca, J.

    2016-06-01

    The gradual spread of urbanization, the phenomenon known under the term urban sprawl, has become one of the paradigms that have characterized the urban development since the second half of the twentieth century and early twenty-first century. However, there is no unanimous consensus about what means "urbanization". The plurality of forms of human settlement on the planet difficult to identify the urbanization processes. The arrival of electrification to nearly every corner of the planet is certainly the first and more meaningful indicator of artificialization of land. In this sense, the paper proposes a new methodology based on the analysis of the satellite image of nighttime lights designed to identify the highly impacted landscapes worldwide and to build an index of Land Impacted by Light per capita (LILpc) as an indicator of the level of urbanization. The used methodology allows the identification of different typologies of urbanized areas (villages, cities or metropolitan areas), as well as "rural", "rurban", "periurban" and "central" landscapes. The study identifies 186,134 illuminated contours (urbanized areas). In one hand, 404 of these contours could be consider as real "metropolitan areas"; and in the other hand, there are 161,821 contours with less than 5,000 inhabitants, which could be identify as "villages". Finally, the paper shows that 44.5 % live in rural areas, 15.5 % in rurban spaces, 26.2 % in suburban areas and only 18.4 % in central areas.

  3. Impacts of Ocean Acidification

    Energy Technology Data Exchange (ETDEWEB)

    Bijma, Jelle (Alfred Wegener Inst., D-27570 Bremerhaven (Germany)) (and others)

    2009-08-15

    There is growing scientific evidence that, as a result of increasing anthropogenic carbon dioxide (CO{sub 2}) emissions, absorption of CO{sub 2} by the oceans has already noticeably increased the average oceanic acidity from pre-industrial levels. This global threat requires a global response. According to the Intergovernmental Panel on Climate Change (IPCC), continuing CO{sub 2} emissions in line with current trends could make the oceans up to 150% more acidic by 2100 than they were at the beginning of the Anthropocene. Acidification decreases the ability of the ocean to absorb additional atmospheric CO{sub 2}, which implies that future CO{sub 2} emissions are likely to lead to more rapid global warming. Ocean acidification is also problematic because of its negative effects on marine ecosystems, especially marine calcifying organisms, and marine resources and services upon which human societies largely depend such as energy, water, and fisheries. For example, it is predicted that by 2100 around 70% of all cold-water corals, especially those in the higher latitudes, will live in waters undersaturated in carbonate due to ocean acidification. Recent research indicates that ocean acidification might also result in increasing levels of jellyfish in some marine ecosystems. Aside from direct effects, ocean acidification together with other global change-induced impacts such as marine and coastal pollution and the introduction of invasive alien species are likely to result in more fragile marine ecosystems, making them more vulnerable to other environmental impacts resulting from, for example, coastal deforestation and widescale fisheries. The Marine Board-ESF Position Paper on the Impacts of Climate Change on the European Marine and Coastal Environment - Ecosystems indicated that presenting ocean acidification issues to policy makers is a key issue and challenge. Indeed, as the consequences of ocean acidification are expected to emerge rapidly and drastically, but are

  4. Degradation of mechanical properties of stainless steel cladding due to neutron irradiation and thermal aging

    International Nuclear Information System (INIS)

    Thermal aging of three-wire series-arc stainless steel weld overlay cladding at 288 degrees C for 1605 h resulted in an appreciable decrease (16%) in the Charpy V-notch (CVN) upper-shelf energy (USE), but the effect on the 41-J transition temperature shift was very small (3 degrees C). The combined effect following neutron irradiation at 288 degrees C to a fluence of 5 X 1019 neutrons/cm2 (>1 MeV) was a 22% reduction in the USE and a 29 degrees C shift in the 41-J transition temperature. The effect of thermal aging on tensile properties was very small. However, the combined effect of irradiation and aging was an increase in the yield strength (6 to 34% at test temperatures from 288 to -125 degrees C) and no apparent change in ultimate tensile strength or total elongation. Neutron irradiation reduced the initiation fracture toughness (Jκ) much more than did thermal aging alone. However, irradiation slightly decreased the tearing modulus but no reduction was caused by thermal aging alone. The effects of long-term thermal exposure times (20,000 and 50,000 h) will be investigated when the specimens become available. Also, long-term thermal exposure of the three-wire cladding as well as type 308 stainless steel weld materials at 343 degrees C is in progress

  5. Effects of thermal aging and neutron irradiation on the mechanical properties of three-wire stainless steel weld overlay cladding

    International Nuclear Information System (INIS)

    Thermal aging of three-wire series-arc stainless steel weld overlay cladding at 288 degrees C for 1605 h resulted in an appreciable decrease (16%) in the Charpy V-notch (CVN) upper-shelf energy (USE), but the effect on the 41-J transition temperature shift was very small (3 degrees C). The combined effect of aging and neutron irradiation at 288 degrees C to a fluence of 5 x 1019 neutrons/cm2 (> 1 MeV) was a 22% reduction in the USE and a 29 degrees C shift in the 41-J transition temperature. The effect of thermal aging on tensile properties was very small. However, the combined effect of irradiation and aging was an increase in the yield strength (6 to 34% at test temperatures from 288 to -125 degrees C) but no apparent change in ultimate tensile strength or total elongation. Neutron irradiation reduced the initiation fracture toughness (JIc) much more than did thermal aging alone. Irradiation slightly decreased the tearing modulus, but no reduction was caused by thermal aging alone. Other results from tensile, CVN, and fracture toughness specimens showed that the effects of thermal aging at 288 or 343 degrees C for 20,000 h each were very small and similar to those at 288 degrees C for 1605 h. The effects of long-term thermal exposure time (50,000 h and greater) at 288 degrees C will be investigated as the specimens become available in 1996 and beyond

  6. Design and fabrication report on instrumented capsule (99M-01K.02H) for korean reactor pressure vessel material made by HANJUNG (Co)

    International Nuclear Information System (INIS)

    The instrumented capsules (99M-01K·02H) was designed and fabricated. The purpose of the capsules were to evaluate the nuclear irradiation performance of the Korean nuclear reactor pressure vessel material, SA508 class 3 steel, fabricated by HANJUNG Co for Yonggwang Units 4,5 and Ulchin Unit 4. There are 5 stages having specimens and independent electric heaters in the capsule mainbody. 12 K-type thermocouples and 5 sets of Ni-Ti-Fe and sapphire neutron Fluence Monitors were also inserted in the apsule. Various types of specimens, such as round compact tension, Charpy insert, pre-cracked v-notch (PCVN), tensile, small punch (SP), magnetic Barkhausen effect (MBE), and transmission electron micrograph (TEM) specimens, were inserted in the capsule. The capsule was fabricated at DAEWOO Precision Co. according to KAERI detailed design specifications. This report describes the details of the design, fabrication and inspection of the 99M-01K and 99M-02H capsule. The capsules were irradiated in the IR2 test hole of HANARO at 290±10 deg C up to the fast neutron fluence (E>1.0 MeV) of 3.0x1019 (n/cm2)

  7. Fracture toughness curves of Japanese reactor pressure vessel steels considering neutron irradiation embrittlement

    International Nuclear Information System (INIS)

    In Japanese nuclear power plants, surveillance tests are conducted according to the Japan Electric Association Code JEAC4201 in order to monitor the degree of embrittlement of reactor pressure vessel (RPV) material due to neutron irradiation. Through the surveillance tests for Pressurized Water Reactor (PWR) plants, a large number of fracture toughness data have been accumulated for Japanese RPV irradiated materials. New fracture toughness curves have been developed adopting the Master Curve (MC) concept and these curves have been correlated with the Charpy V-notch 30 ft-lb transition temperature, Tr30 for evaluation against Pressurized Thermal Shock (PTS) events. The developed curves are also intended to represent the 5% tolerance lower bound of fracture toughness trend incorporating fracture toughness variation depending on the product form, which consists of plates, forgings and weld metals. In this study, the reliability of the curves is evaluated for predicted Tr30 values in consideration of application to PTS evaluation for Japanese PWR plants and it was demonstrated that the developed lower bound curve has reliability comparable to that for the measured Tr30 by adding a margin of 3degC to the predicted Tr30. (author)

  8. Evaluation of the mechanical properties after thermal treatment of a structural hot rolled multiphase steels

    International Nuclear Information System (INIS)

    The present paper corresponds to the experimental study conducted on a hot rolled (HR)multiphase (MP) steel, in which hardness, tensile and toughness properties were measured after the application of a series of subcritical and inter critical heat treatments (HT) to the hot rolled stock. The aforementioned values were compared to the corresponding ones in the as-rolled state and after normalizing. The microstructure in the longitudinal plane of the strip was analyzed by light optical microscopy in the as-rolled state and in the HT sample. Longitudinal (L) and transverse (T) tensile and toughness specimens were cut to characterize every condition studied. toughness properties were evaluated by means of Charpy V-notch tests conducted at 20 degree centigree, 0 degree centigree, -20 degree centigree, -40 degree centigree, -60 degree centigree and -80 degree centigree. It was observed that the yield stress increased with the increase in the heat treatment temperature in the subcritical range, while the tensile strength decreased slightly over the same range of temperatures. Uniform and total elongation only showed a slight improvement when the treatment was conducted at 620 degree centigree and 700 degree centigree, while the best toughness response corresponded to the sample treated at 500 degree centigree for operating temperatures comprised between -40 degree centigree and room temperatures (RT). (Author) 13 refs

  9. Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components

    International Nuclear Information System (INIS)

    The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950's are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (En > 0.1 MeV) and displacements per atom (dpa)3. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR)

  10. Reactor pressure vessel structural integrity research

    Energy Technology Data Exchange (ETDEWEB)

    Pennell, W.E.; Corwin, W.R. [Oak Ridge National Lab., TN (United States)

    1995-04-01

    Development continues on the technology used to assess the safety of irradiation-embrittled nuclear reactor pressure vessels (RPVs) containing flaws. Fracture mechanics tests on RPV steel, coupled with detailed elastic-plastic finite-element analyses of the crack-tip stress fields, have shown that (1) constraint relaxation at the crack tip of shallows surface flaws results in increased data scatter but no increase in the lower-bound fracture toughness, (2) the nil ductility temperature (NDT) performs better than the reference temperature for nil ductility transition (RT{sub NDT}) as a normalizing parameter for shallow-flaw fracture toughness data, (3) biaxial loading can reduce the shallow-flaw fracture toughness, (4) stress-based dual-parameter fracture toughness correlations cannot predict the effect of biaxial loading on a shallow-flaw fracture toughness because in-plane stresses at the crack tip are not influenced by biaxial loading, and (5) an implicit strain-based dual-parameter fracture toughness correlation can predict the effect of biaxial loading on shallow-flaw fracture toughness. Experimental irradiation investigations have shown that (1) the irradiation-induced shift in Charpy V-notch vs temperature behavior may not be adequate to conservatively assess fracture toughness shifts due to embrittlement, and (2) the wide global variations of initial chemistry and fracture properties of a nominally uniform material within a pressure vessel may confound accurate integrity assessments that require baseline properties.

  11. Fractographic study of a thick wall pressure vessel failure

    International Nuclear Information System (INIS)

    The pressure vessel described in this paper is identified as Intermediate Test Vessel 1 (ITV-1) and was fabricated of SA508, Class 2 Steel. It was tested to failure at 540C (1300F). The gross failure appeared to be a brittle fracture although accompanied by a measured strain of 0.9%. Seven regions of the fracture were examined in detail and the observed surfaces were compared to Charpy V-notch (C/sub v/) specimens of SA508, Class 2 steel broken at temperatures above and below the ductile to brittle transition temperature. Three samples from the vessel were taken in the region around the fatigue notch and four from areas well removed from the notch. All these were carefully examined both optically and by scanning electron microscopy (SEM). It was established that early crack extension was by ductile mode until a large flaw approximately 500 mm long 83 mm wide was developed. At this point the vessel could no longer contain the internal pressure and final rupture was by brittle fracture

  12. Design and fabrication report on instrumented capsule (99M-01K.02H) for korean reactor pressure vessel material made by HANJUNG (Co)

    Energy Technology Data Exchange (ETDEWEB)

    Choo, K. N.; Kang, Y. H.; Kim, B. G.; Cho, M. S.; Son, J. M.; Kim, D. S.; Oh, J. M.; Park, S. J.; Shin, Y. T

    2000-09-01

    The instrumented capsules (99M-01K{center_dot}02H) was designed and fabricated. The purpose of the capsules were to evaluate the nuclear irradiation performance of the Korean nuclear reactor pressure vessel material, SA508 class 3 steel, fabricated by HANJUNG Co for Yonggwang Units 4,5 and Ulchin Unit 4. There are 5 stages having specimens and independent electric heaters in the capsule mainbody. 12 K-type thermocouples and 5 sets of Ni-Ti-Fe and sapphire neutron Fluence Monitors were also inserted in the apsule. Various types of specimens, such as round compact tension, Charpy insert, pre-cracked v-notch (PCVN), tensile, small punch (SP), magnetic Barkhausen effect (MBE), and transmission electron micrograph (TEM) specimens, were inserted in the capsule. The capsule was fabricated at DAEWOO Precision Co. according to KAERI detailed design specifications. This report describes the details of the design, fabrication and inspection of the 99M-01K and 99M-02H capsule. The capsules were irradiated in the IR2 test hole of HANARO at 290{+-}10 deg C up to the fast neutron fluence (E>1.0 MeV) of 3.0x10{sup 19} (n/cm{sup 2})

  13. Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, R.L.; Caskey, G.R. Jr.

    1991-12-01

    The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950's are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

  14. Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, R.L.; Caskey, G.R. Jr.

    1991-12-01

    The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950`s are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

  15. Analysis of fracture toughness in the transition-temperature region of an Mn-Mo-Ni low-alloy steel

    Science.gov (United States)

    Kim, Sangho; Hwang, Byoungchul; Lee, Sunghak; Lee, Sunghak

    2003-06-01

    This study is concerned with the analysis of fracture toughness in the transition region of an Mn-Mo-Ni low-alloy steel, in accordance with the ASTM E1921 standard test method. Elastic-plastic cleavage fracture toughness ( K Jc ) was determined by three-point bend tests, using precracked Charpy V-notch (PCVN) specimens, and relationships between K Jc , the critical component of J ( J c ), critical distance ( X c ), stretch-zone width (SZW), local fracture stress, and plane-strain fracture toughness ( K Ic were discussed on the basis of the cleavage fracture behavior in the transition region. The master curve and the 95 pct confidence curves well explained the variation in the measured K Jc , and the Weibull slope measured on the Weibull plots was consistent with the theoretical slope of 4. Fractographic observation indicated that X c linearly increased with increasing J c , and that the SZW had a good correlation with K Jc , irrespective of the test temperature. In addition, the local fracture stress was independent of the test temperature, because the tempered bainitic steel used in this study showed a propagation-controlled cleavage fracture behavior.

  16. Effects of grain size on fracture toughness in transition temperature region of Mn-Mo-Ni low-alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sangho; Lee, Sunghak; Lee, Bong Sang

    2003-10-25

    An investigation was conducted into the effect of grain size on fracture toughness in the transition temperature region of Mn-Mo-Ni low-alloy steels used for nuclear pressure vessels. Three kinds of steels with different austenite grain sizes (AGS) were fabricated by varying the contents of Al and N, and their microstructures and mechanical properties were examined. Elastic-plastic cleavage fracture toughness, K{sub Jc}, was determined by three-point bend tests of precracked Charpy V-notch (PCVN) specimens according to ASTM E1921 standard test method. When the AGS decreased, the total number of carbides increased, while the size and the aspect ratio of carbides decreased. Local fracture stresses, estimated from a theoretical stress distribution in front of a crack tip, were found to be mainly determined by the 92nd% size of carbides. Cross-sectional areas beneath fracture surfaces were observed to understand microstructural features to affect the cleavage crack propagation behavior. The results showed that measured cleavage fracture units were smaller than AGSs, indicating that packet boundaries as well as austenite grain boundaries played an important role in the cleavage crack propagation. Based on the electron back-scatter diffraction (EBSD) results, the cleavage fracture units could also be matched with the effective grain sizes determined by the misorientation tolerance angle of 25 deg.

  17. Relationship between grain size and fracture toughness in transition region of Mn-Mo-Ni low-alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Ho; Lee, Sung Hak [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of); Oh, Yong Jun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2002-03-01

    The present study aims at interpreting the effect of grain size on fracture toughness in the transition region of Mn-Mo-Ni low-alloy steels. Three kinds of steels with different austenite grain sizes were fabricated, and their microstructures and mechanical properties were examined. Elastic-plastic cleavage fracture toughness, K{sub Jc}, was determined by 3-point bend tests of precracked Charpy V-notch (PCVN) specimens according to ASTM E1921 standard test method. When the austenite grain size decreased, the total number of carbides increased, while the size and the aspect ratio of carbides decreased. Local fracture stresses, estimated from a theoretical stress distribution in front of a crack tip, were found to be mainly determined by the 92%th size of carbides. Cross-sectional areas beneath fracture surfaces were observed to understand microstructural features to affect the cleavage crack propagation behavior. The results showed that measured cleavage fracture units were smaller than austenite grain sizes, indicating that packet boundaries as well as austenite grain boundaries played an important role in the cleavage crack propagation. Based on the electron back-scatter diffraction (EBSD) results, the cleavage fracture units could also be matched with the effective grain sizes determined by the misorientation tolerance angle of 25 degree.

  18. Correlation between radiation damage and magnetic properties in reactor vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Kempf, R.A., E-mail: kempf@cnea.gov.ar [División Caracterización, GCCN, CAC-CNEA (Argentina); Sacanell, J. [Departamento Física de la Materia Condensada, GIyA, CAC-CNEA, CONICET (Argentina); Milano, J. [División Resonancias Magnéticas, CAB-CNEA, CONICET (Argentina); Guerra Méndez, N. [Departamento Física de la Materia Condensada, GIyA, CAC-CNEA, CONICET (Argentina); Winkler, E.; Butera, A. [División Resonancias Magnéticas, CAB-CNEA, CONICET (Argentina); Troiani, H. [División Física de Metales, CAB-CNEA and Instituto Balseiro (UNCU), CONICET (Argentina); Saleta, M.E. [División Resonancias Magnéticas, CAB-CNEA, CONICET (Argentina); Fortis, A.M. [Departamento Estructura y Comportamiento. Gerencia Materiales-GAEN, CAC-CNEA (Argentina)

    2014-02-01

    Since reactor pressure vessel steels are ferromagnetic, provide a convenient means to monitor changes in the mechanical properties of the material upon irradiation with high energy particles, by measuring their magnetic properties. Here, we discuss the correlation between mechanical and magnetic properties and microstructure, by studying the flux effect on the nuclear pressure vessel steel used in reactors currently under construction in Argentina. Charpy-V notched specimens of this steel were irradiated in the RA1 experimental reactor at 275 °C with two lead factors (LFs), 93 and 183. The magnetic properties were studied by means of DC magnetometry and ferromagnetic resonance. The results show that the coercive field and magnetic anisotropy spatial distribution are sensitive to the LF and can be explained by taking into account the evolution of the microstructure with this parameter. The saturation magnetization shows a dominant dependence on the accumulated damage. Consequently, the mentioned techniques are suitable to estimate the degradation of the reactor vessel steel.

  19. Resolution of the Task A-11 reactor-vessel materials-toughness safety issue. Part I. Main report. Part II. Staff responses to public comments, and Appendices A and B

    International Nuclear Information System (INIS)

    This report provides the NRC position with respect to the reactor pressure vessel safety analysis required according to the rules given in the Code of Federal Regulations, Title 10 (10 CFR). An analysis is required whenever neutron irradiation reduces the Charpy V-notch upper shelf energy level in the vessel steel to 50 ft-lb or less. Task A-11 was needed because the available engineering methodology for such an analysis utilized linear elastic fracture mechanics principles, which could not fully account for the plastic deformation or stable crack extension expected at upper shelf temperatures. The Task A-11 goal was to develop an elastic-plastic fracture mechanics methodology, applicable to the beltline region of a pressurized water reactor vessel, which could be used in the required safety analysis. The goal was achieved with the help of a team of recognized experts. Part I of this volume contains the For Comment NUREG-0744, originally published in September 1981 and edited to accommodate comments from the public and the NRC staff. Edited segments are noted by vertical marginal lines. Part II of this volume contains the staff's responses to, and resolution of, the public comments received

  20. Results of examinations of pressure vessel samples and instrument nozzles from the TMI-2 lower head

    International Nuclear Information System (INIS)

    Fifteen prism-shaped steel samples were removed from the lower head of the damaged TMI-2 reactor pressure vessel to assess the effects of approximately 19 metric tons of molten core debris that had relocated there during the 1979 loss-of-coolant accident. Metallographic examinations of the samples revealed that inside surface temperatures of 800 to 1,100 degree C were attained during the accident in an elliptical shaped ''hot spot'' ∼1 x 0.7 m. Tensile, creep, and Charpy V-notch specimens were also cut from the samples to assess the mechanical properties of the lower head material at temperatures up to the peak accident temperature. These properties were used in a margin to failure analysis of the lower head. Examinations of instrument nozzles removed from the lower head region assisted in defining the relocation scenario of the molten core debris and showed that the lower head was largely protected from catastrophic failure by a solidified layer around the molten core debris that acted as a partial thermal insulator

  1. Temper embrittlement of cast duplex stainless steels after long-term aging

    International Nuclear Information System (INIS)

    Microstructural changes and fracture behavior in cast CF8M duplex stainless steel after aging at 300 to 450degC for 300 to 10000 h have been investigated. Both, optical microscopical and transmission electron microscopical analyses, hardness and ferrite content measurements have been carried out in this study. Strengthening and overaging phenomena of the ferrite phase have been identified by hardness measurements. Spinodal decomposition and heterogeneous precipitation of G-phase were found to be responsible for strengthening of the ferrite phase after aging with a temper parameter P in the range ca. 1.8 to 4.0. Homogeneous precipitation of noncoherent α'- and G-phases in ferrite, identified by both optical and transmission electron microscopical analyses for aging with P > 4.0 at 450degC, is associated with overaging phenomena. Three different fracture modes, dimples, cleavage and α/γ grain boundary separation, have been observed for Charpy V-notch and CT test specimens fractured at +20degC. (author)

  2. Predicting the toughness of SMA austenitic stainless steel welds at 77 K

    International Nuclear Information System (INIS)

    Austenitic stainless steels often provide the best combination of strength and toughness for cryogenic applications: however, the weld toughness is frequently much lower than that of the base metal. This study proposes a more accurate and simpler model for developing improved filler metal compositions. Several previous studies of the weld toughness were analyzed separately and in combination using a stepwise regression method and an expanded variable list. The total data base consisted of chemical composition, ferrite number (FN), and the Charpy V-notch (CVN) toughness at 77 K of 79 austenitic stainless steel welds deposited by the shielded metal arc process. Analysis of the complete data base revealed that the FN calculated from the Schaeffler diagram was the most significant variable for predicting the CVN toughness. The predictive equation produced a better correlation between the measured and predicted values of weld toughness than the previously published predictive equations. The group of 36 fully austenitic welds and the group of 21 type 316 welds in the data base were analyzed by the same procedure. In both cases the ferrite number was found to be the most significant predictor of toughness

  3. Microsegregation in a F82H plate

    Energy Technology Data Exchange (ETDEWEB)

    Sakasegawa, H., E-mail: sakasegawa.hideo@jaea.go.jp [Japan Atomic Energy Egency (JAEA), Fusion Research and Development Directorate, Division of Rokassho BA Project, Structural Materials Development Group, 2-166 Omotedate, Obuchi, Rokkasho, Aomori 039-3212 (Japan); Tanigawa, H. [Japan Atomic Energy Egency (JAEA), Fusion Research and Development Directorate, Division of Rokassho BA Project, Structural Materials Development Group, 2-166 Omotedate, Obuchi, Rokkasho, Aomori 039-3212 (Japan)

    2013-11-15

    Electron probe microanalysis (EPMA) on F82H heats revealed microsegregation of at least four metallic elements, including chromium, tungsten, vanadium, and manganese. Segregation of these elements was observed as a band-like structure parallel to the rolling direction. The maximum difference in tungsten content due to the tungsten segregation was about 1.0 wt.% between the bands. This difference in the tungsten content affected the tungsten contents in both the matrix and precipitates. In particular, precipitation morphology was affected after aging at 923 K for 2000 h. Laves phase, (Fe, Cr){sub 2}W, precipitated along tungsten-enriched bands in the aged specimen. Consequently, these aligned Laves phases decreased USE (upper shelf energy) by about 20% for the Charpy specimens with a V-notch parallel to the segregation band. Thus, we also tried to find appropriate homogenizing conditions to diminish such microsegregation and suggested the condition of 144 h at 1453 K. This condition did not form δ-ferrite, which is known to be a phase harmful to material toughness.

  4. Microstructure and mechanical properties of SA508-3 steel weldments with submerged arc welding

    International Nuclear Information System (INIS)

    The present study was to investigate the effect of energy input on the microstructure, tensile properties and toughness of single-pass submerged arc bead-in-groove welds produced on RPV SA508 class 3 steels. The heat input was varied in the range of 1.6, 3.2 and 5.0 kJ/mm. The toughness of weld metals was evaluated by using subsize Charpy V-notch specimens in the temperature range of -190 .deg. C to 20 .deg. C. The weld microstructure and fractography were observed by optical and scanning electron microscopies, respectively. With increasing heat inputs, tensile strength and hardness of weld metals were decreased while elongation was increased. The poor notch toughness at 1.6 kJ/mm was attributed to the formation of ferrite with aligned second phase and banitic microstructure with high yield strength while that at 5.0 kJ/mm was due to the presence of grain boundary and polygonal ferrites. The microstructure of the intermediate energy input welds consisted of a high proportion of acicular ferrite with limited polygonal ferrites, which provide improved notch toughness

  5. Different approaches to estimation of RPV material embrittlement

    International Nuclear Information System (INIS)

    The surveillance test data for the nuclear power plant which is under operation in Ukraine have been used to estimate WWER-1000 RPV material embrittlement. The beltline materials (base and weld metal) were characterized using Charpy impact and fracture toughness test methods. The fracture toughness test data were analyzed according to the standard ASTM 1921-05. The pre-cracked Charpy specimens were tested to estimate a shift of reference temperature T0 due to neutron irradiation. The maximum shift of reference temperature T0 is 84 deg C. A radiation embrittlement rate AF for the RPV material was estimated using fracture toughness test data. In addition the AF factor based on the Charpy curve shift (δTF) has been evaluated. A comparison of the AF values estimated according to different approaches has shown there is a good agreement between the radiation shift of Charpy impact and fracture toughness curves. Therefore Charpy impact test data can be successfully applied to estimate the fracture toughness curve shift and therefore embrittlement rate. Furthermore it was revealed that radiation embrittlement rate for weld metal is higher than predicted by a design relationship. The enhanced embrittlement is most probably related to simultaneously high nickel and high manganese content in weld metal

  6. Volcanoes: observations and impact

    Science.gov (United States)

    Thurber, Clifford; Prejean, Stephanie G.

    2012-01-01

    Volcanoes are critical geologic hazards that challenge our ability to make long-term forecasts of their eruptive behaviors. They also have direct and indirect impacts on human lives and society. As is the case with many geologic phenomena, the time scales over which volcanoes evolve greatly exceed that of a human lifetime. On the other hand, the time scale over which a volcano can move from inactivity to eruption can be rather short: months, weeks, days, and even hours. Thus, scientific study and monitoring of volcanoes is essential to mitigate risk. There are thousands of volcanoes on Earth, and it is impractical to study and implement ground-based monitoring at them all. Fortunately, there are other effective means for volcano monitoring, including increasing capabilities for satellite-based technologies.

  7. Volcanoes, Observations and Impact

    Science.gov (United States)

    Thurber, Clifford; Prejean, Stephanie

    Volcanoes are critical geologic hazards that challenge our ability to make long-term forecasts of their eruptive behaviors. They also have direct and indirect impacts on human lives and society. As is the case with many geologic phenomena, the time scales over which volcanoes evolve greatly exceed that of a human lifetime. On the other hand, the time scale over which a volcano can move from inactivity to eruption can be rather short: months, weeks, days, and even hours. Thus, scientific study and monitoring of volcanoes is essential to mitigate risk. There are thousands of volcanoes on Earth, and it is impractical to study and implement ground-based monitoring at them all. Fortunately, there are other effective means for volcano monitoring, including increasing capabilities for satellite-based technologies.

  8. CITYZEN climate impact studies

    Energy Technology Data Exchange (ETDEWEB)

    Schutz, Martin (ed.)

    2011-07-01

    We have estimated the impact of climate change on the chemical composition of the troposphere due to changes in climate from current climate (2000-2010) looking 40 years ahead (2040-2050). The climate projection has been made by the ECHAM5 model and was followed by chemistry-transport modelling using a global model, Oslo CTM2 (Isaksen et al., 2005; Srvde et al., 2008), and a regional model, EMEP. In this report we focus on carbon monoxide (CO) and surface ozone (O3) which are measures of primary and secondary air pollution. In parallel we have estimated the change in the same air pollutants resulting from changes in emissions over the same time period. (orig.)

  9. Second Impact Syndrome

    Directory of Open Access Journals (Sweden)

    Bey, Tareg

    2009-02-01

    Full Text Available A controversial term first described by Saunders and Harbaugh1 in 1984, Second Impact Syndrome (SIS consists of two events. Typically, it involves an athlete suffering post-concussive symptoms following a head injury.2 If, within several weeks, the athlete returns to play and sustains a second head injury, diffuse cerebral swelling, brain herniation, and death can occur. SIS can occur with any two events involving head trauma. While rare, it is devastating in that young, healthy patients may die within a few minutes. Emergency physicians should be aware of this syndrome and counsel patients and their parents concerning when to allow an athlete to return to play. Furthermore, we present guidelines for appropriate follow up and evaluation by a specialist when necessary.[WestJEM. 2009;10:6-10.

  10. Accounting for Universities’ Impact

    DEFF Research Database (Denmark)

    Perkmann, Markus; Fini, Riccardo; Ross, Jan-Michael;

    2015-01-01

    We present an approach that aims to comprehensively account for scientists’ academic engagement and commercialization activities. While previous research has pointed to the economic and social impact of these activities, it has also been hampered by the difficulties of accurately quantifying them....... Our approach complements university administrative records with data retrieved from external sources and surveys to quantify academic consulting, patenting, and academic entrepreneurship. This allows us to accurately account for ‘independent’ activity, i.e., academic engagement and commercialization...... by not accounting for independent activities. However, with the exception of consulting, we find no significant differences between individuals involved in supported (university-recorded) and independent activity, respectively. Our study contributes to work concerned with developing appropriate and accurate...

  11. Biogenic Impact on Materials

    Science.gov (United States)

    Stephan, Ina; Askew, Peter; Gorbushina, Anna; Grinda, Manfred; Hertel, Horst; Krumbein, Wolfgang; Müller, Rolf-Joachim; Pantke, Michael; Plarre, Rüdiger (Rudy); Schmitt, Guenter; Schwibbert, Karin

    Materials as constituents of products or components of technical systems rarely exist in isolation and many must cope with exposure in the natural world. This chapter describes methods that simulate how a material is influenced through contact with living systems such as microorganisms and arthropods. Both unwanted and desirable interactions are considered. This biogenic impact on materials is intimately associated with the environment to which the material is exposed (Materials-Environment Interaction, Chap. 15). Factors such as moisture, temperature and availability of food sources all have a significant influence on biological systems. Corrosion (Chap. 12) and wear (Chap. 13) can also be induced or enhanced in the presence of microorganisms. Section 14.1 introduces the categories between desired (biodegradation) and undesired (biodeterioration) biological effects on materials. It also introduces the role of biocides for the protection of materials. Section 14.2 describes the testing of wood as a building material especially against microorganisms and insects. Section 14.3 characterizes the test methodologies for two other groups of organic materials, namely polymers (Sect. 14.3.1) and paper and textiles (Sect. 14.3.2). Section 14.4 deals with the susceptibility of inorganic materials such as metals (Sect. 14.4.1), concrete (Sect. 14.4.2) and ceramics (Sect. 14.4.3) to biogenic impact. Section 14.5 treats the testing methodology concerned with the performance of coatings and coating materials. In many of these tests specific strains of organisms are employed. It is vital that these strains retain their ability to utilize/attack the substrate from which they were isolated, even when kept for many years in the laboratory. Section 14.6 therefore considers the importance of maintaining robust and representative test organisms that are as capable of utilizing a substrate as their counterparts in nature such that realistic predictions of performance can be made.

  12. Communication impacting financial markets

    Science.gov (United States)

    Vitting Andersen, Jørgen; Vrontos, Ioannis; Dellaportas, Petros; Galam, Serge

    2014-10-01

    Since the attribution of the Nobel prize in 2002 to Kahneman for prospect theory, behavioral finance has become an increasingly important subfield of finance. However the main parts of behavioral finance, prospect theory included, understand financial markets through individual investment behavior. Behavioral finance thereby ignores any interaction between participants. We introduce a socio-financial model (Vitting Andersen J. and Nowak A., An Introduction to Socio-Finance (Springer, Berlin) 2013) that studies the impact of communication on the pricing in financial markets. Considering the simplest possible case where each market participant has either a positive (bullish) or negative (bearish) sentiment with respect to the market, we model the evolution of the sentiment in the population due to communication in subgroups of different sizes. Nonlinear feedback effects between the market performance and changes in sentiments are taken into account by assuming that the market performance is dependent on changes in sentiments (e.g., a large sudden positive change in bullishness would lead to more buying). The market performance in turn has an impact on the sentiment through the transition probabilities to change an opinion in a group of a given size. The idea is that if for example the market has observed a recent downturn, it will be easier for even a bearish minority to convince a bullish majority to change opinion compared to the case where the meeting takes place in a bullish upturn of the market. Within the framework of our proposed model, financial markets stylized facts such as volatility clustering and extreme events may be perceived as arising due to abrupt sentiment changes via ongoing communication of the market participants. The model introduces a new volatility measure which is apt of capturing volatility clustering and from maximum-likelihood analysis we are able to apply the model to real data and give additional long term insight into where a market is

  13. Pengaruh Kecepatan Pengelasan pada Submerged Arc Welding Baja SM 490 Terhadap Ketangguhan Beban Impak

    Directory of Open Access Journals (Sweden)

    Suharno Suharno

    2004-01-01

    Full Text Available The effect of welding speed of SM 490 steel submerged arc welded on impact charpy toughness was investigated. The welding speed is one of the parameter that affecting physics and mechanical properties, specially the impact charpy toughness. The result show that the welding speed of 6,35 mm/s give the highest impact toughness of 1,825 joule/mm2. Abstract in Bahasa Indonesia : Pengaruh kecepatan pengelasan pada submerged arc welding (SAW atau pengelasan busur terendam baja SM 490 terhadap ketangguhan beban impak telah diselidiki. Kecepatan pengelasan merupakan salah satu parameter pengelasan yang berpengaruh terhadap sifat fisis dan mekanis, khususnya ketangguhan impak charpy. Hasil penelitian menunjukkan bahwa ketangguhan impak tertinggi sebesar 1,825 Joule/mm2, diperoleh pada kecepatan pengelasan 6,35 mm/s. Kata kunci: Las busur rendam, kecepatan pengelasan, ketangguhan impak.

  14. Effect of constituent phase on mechanical properties of 9Cr–1WVTa reduced activation ferritic–martensitic steels

    International Nuclear Information System (INIS)

    Influence of the formation of ferrite and accompanying carbides in martensite matrix on the tensile and Charpy impact properties was investigated for reduced activation ferritic–martensitic (RAFM) 9Cr–1WVTa steel. As the fractions of ferrite and carbide adjacent to the ferrite grain boundary increase, both tensile and Charpy impact properties deteriorated in as-normalized condition. In particular, the tensile strength and elongation decreased simultaneously, which is believed to be led by the localized deformation in ferrite which is softer than martensite, promoting the formation and growth of voids. In addition, the formation of ferrite was also detrimental to the Charpy impact properties regarding to the absorbed energy because the precipitation of carbides around ferrite were vulnerable to the nucleation and propagation of cleavage cracks. The degradation of tensile properties can be recovered by tempering, but the DBTT temperature still increases with presence of ferrite

  15. A study on NDE method of thermal aging of cast duplex stainless steels

    International Nuclear Information System (INIS)

    To maintain the integrity of applications of the duplex stainless steels currently in service, a study was conducted to develop a method to nondestructively estimate their Charpy-impact energy at room temperature. It was found that hardness of the ferrite phase is a reliable indicator of the process of embrittlement during long-term heating of duplex stainless steels. However, further information on the ferrite phase and the austenite phase is required for the estimation of Charpy-impact energy. An equation composed of the hardness values of ferrite and austenite phases, the ferrite content and the average spacing of ferrite phase islands was presented as a method applicable to the nondestructive estimation of Charpy-impact energy at room temperature. (orig.)

  16. [Impacts of numerology on acupuncture].

    Science.gov (United States)

    Chen, Min; Wu, Changqiu; Wu, Xueyi

    2016-04-01

    Numerology has a long history in China and has the profound impacts on every academic field in TCM, with acupuncture involved. In this paper, the impacts on acupuncture were discussed in different aspects such as the numbers of meridians, the length of meridian, the time taboo of acupuncture, acupuncture manipulation and time acupuncture. It was found that numerology had laid the critical impact on acupuncture and had the profound imprint nowadays. It is of great significance to study the numerology theory in its impacts on acupuncture, in the exploration on the theories behind acupuncture as well as the comprehensive understanding of acupuncture. PMID:27352509

  17. Tracking digital impact: the challenge of evidencing impact

    OpenAIRE

    Tait, Elizabeth; Holden, Jennifer

    2012-01-01

    How can we prove that academic presence on social media is creating an impact? Elizabeth Tait and Jennifer Holden question how to demonstrate more than just a social media presence as they develop a standard for assessing the impact of digital engagement.

  18. Impact Cratering Calculations

    Science.gov (United States)

    Ahrens, Thomas J.

    2001-01-01

    We examined the von Mises and Mohr-Coulomb strength models with and without damage effects and developed a model for dilatancy. The models and results are given in O'Keefe et al. We found that by incorporating damage into the models that we could in a single integrated impact calculation, starting with the bolide in the atmosphere produce final crater profiles having the major features found in the field measurements. These features included a central uplift, an inner ring, circular terracing and faulting. This was accomplished with undamaged surface strengths of approximately 0.1 GPa and at depth strengths of approximately 1.0 GPa. We modeled the damage in geologic materials using a phenomenological approach, which coupled the Johnson-Cook damage model with the CTH code geologic strength model. The objective here was not to determine the distribution of fragment sizes, but rather to determine the effect of brecciated and comminuted material on the crater evolution, fault production, ejecta distribution, and final crater morphology.

  19. The Impact of Odors

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The odor microclimate is formed by gaseous airborne components perceived either as an unpleasant smell or as a pleasant smell. Smells enter the building interior partly from outdoors (exhaust fumes - flower fragrance and partly from indoors (building materials, smoking cigarettes - cosmetics, dishes. They affect the human organism through the olfactory center which is connected to the part of brain that is responsible for controlling people’s emotions and sexual feelings: smells therefore participate to a high level in mood formation. The sense of smell diminishes slowly in people over the age of 60, but all female age categories have a better sense of smell than males. Smell is extremely sensitive, e.g., during pregnancy, or if an illness is coming. Bad smells cause a decrease in human performance, loss of concentration, and loss of taste. Sweet smells have a positive impact on human feelings and on human performance. Criteria for odor microclimate appraisal are presented (concentration limits of CO2 , TVOC, plf, decipol, decicarbdiox, decitvoc.

  20. Research Impact and Educational Research

    Science.gov (United States)

    Oancea, Alis

    2013-01-01

    Based on a 2010-11 study involving senior researchers from seven disciplines, this article explores critically some of the diverse interpretations of impact in different disciplines, sub-fields and modes of research, and researchers' views about how these interpretations articulate with top-down impact agendas and with university structures…

  1. Caecal impaction in a dog

    International Nuclear Information System (INIS)

    A seven-year-old, intact male dobermann with a four-week history of anorexia was diagnosed as having impaction of the caecum with inspissated faeces. Radiographic and histopathological findings revealed impaction of the caecum and a mild subacute locally extensive typhlitis. Typhlectomy was curative and no further problems have been reported

  2. Assessing Cross-Media Impacts

    Science.gov (United States)

    Reiquam, Howard; And Others

    1975-01-01

    Using 1000 MW coal-fired central power stations as an example, the impacts upon other media (land, air, water) are analyzed when controls are imposed on one medium. The development of a methodology for assessing the cross-media impact of specific control technologies or strategies is illustrated. (Author/BT)

  3. Developments in Social Impact Assessment

    NARCIS (Netherlands)

    Vanclay, Frank

    2014-01-01

    Along with environmental impact assessment, social impact assessment (SIA) has its origins in the 1970s and has developed from being a tool to meet regulatory requirements, to a discipline that seeks to contribute proactively to better project and policy development and to enhance the wellbeing of a

  4. Southern Impact Testing Alliance (SITA)

    Science.gov (United States)

    Hubbs, Whitney; Roebuck, Brian; Zwiener, Mark; Wells, Brian

    2009-01-01

    Efforts to form this Alliance began in 2008 to showcase the impact testing capabilities within the southern United States. Impact testing customers can utilize SITA partner capabilities to provide supporting data during all program phases-materials/component/ flight hardware design, development, and qualification. This approach would allow programs to reduce risk by providing low cost testing during early development to flush out possible problems before moving on to larger scale1 higher cost testing. Various SITA partners would participate in impact testing depending on program phase-materials characterization, component/subsystem characterization, full-scale system testing for qualification. SITA partners would collaborate with the customer to develop an integrated test approach during early program phases. Modeling and analysis validation can start with small-scale testing to ensure a level of confidence for the next step large or full-scale conclusive test shots. Impact Testing Facility (ITF) was established and began its research in spacecraft debris shielding in the early 1960's and played a malor role in the International Space Station debris shield development. As a result of return to flight testing after the loss of STS-107 (Columbia) MSFC ITF realized the need to expand their capabilities beyond meteoroid and space debris impact testing. MSFC partnered with the Department of Defense and academic institutions as collaborative efforts to gain and share knowledge that would benefit the Space Agency as well as the DoD. MSFC ITF current capabilities include: Hypervelocity impact testing, ballistic impact testing, and environmental impact testing.

  5. The impact of 'terminator' technology

    NARCIS (Netherlands)

    Visser, B.; Meer, van der I.J.M.; Louwaars, N.; Beekwilder, J.; Eaton, D.

    2001-01-01

    Genetic use-restriction technologies enable the developers of transgenic plants or animals to protect their variety or breed from unauthorized use in a biological way. The use of 'terminator technology' can have different impacts on farmers and breeders. If the technology is effective, it impacts on

  6. Black hole accretion disc impacts

    Science.gov (United States)

    Pihajoki, P.

    2016-04-01

    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength λ = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  7. Black hole accretion disc impacts

    CERN Document Server

    Pihajoki, Pauli

    2015-01-01

    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength {\\lambda} = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  8. Ejecta evolution during cone impact

    KAUST Repository

    Marston, Jeremy

    2014-07-07

    We present findings from an experimental investigation into the impact of solid cone-shaped bodies onto liquid pools. Using a variety of cone angles and liquid physical properties, we show that the ejecta formed during the impact exhibits self-similarity for all impact speeds for very low surface tension liquids, whilst for high-surface tension liquids similarity is only achieved at high impact speeds. We find that the ejecta tip can detach from the cone and that this phenomenon can be attributed to the air entrainment phenomenon. We analyse of a range of cone angles, including some ogive cones, and impact speeds in terms of the spatiotemporal evolution of the ejecta tip. Using superhydrophobic cones, we also examine the entry of cones which entrain an air layer.

  9. Guidance law with impact time and impact angle constraints

    Institute of Scientific and Technical Information of China (English)

    Zhang Youan; Ma Guoxin; Liu Aili

    2013-01-01

    A novel closed-form guidance law with impact time and impact angle constraints is proposed for salvo attack of anti-ship missiles,which employs missile's normal acceleration (not jerk) as the control command directly.Firstly,the impact time control problem is formulated as tracking the designated time-to-go (the difference between the designated impact time and the current flight time) for the actual time-to-go of missile,and the impact angle control problem is formulated as tracking the designated heading angle for the actual heading angle of missile.Secondly,a biased proportional navigation guidance (BPNG) law with designated heading angle constraint is constructed,and the actual time-to-go estimation for this BPNG is derived analytically by solving the system differential equations.Thirdly,by adding a feedback control to this constructed BPNG to eliminate the time-to-go error-the difference between the standard time-to-go and the actual time-to-go,a guidance law with adjustable coefficients to control the impact time and impact angle simultaneously is developed.Finally,simulation results demonstrate the performance and feasibility of the proposed approach.

  10. Microstructure and mechanical properties of a W–2wt.%Y2O3 composite produced by sintering and hot forging

    International Nuclear Information System (INIS)

    A W–2Y2O3 composite has been developed by powder metallurgy methods in collaboration with the Plansee Company (Austria). The microstructure of the composite was analyzed using transmission electron microscopy and electron backscatter diffraction in scanning electron microscopy. The mechanical properties of the composite were analyzed using nano-indentation experiments, tensile and Charpy impact tests. It was mainly found that the composite exhibits ductile tensile behavior at 673–1273 K but weak Charpy impact properties, characterized by low absorbed energy values, at 773–1273 K

  11. Microstructural and Fractographic Characterization of a Thermally Embrittled Nuclear Grade Steel: Part I - Annealing

    Directory of Open Access Journals (Sweden)

    Tarpani José R.

    2002-01-01

    Full Text Available A nuclear reactor pressure vessel steel was submitted to different annealing heat treatments aimed at simulating neutron irradiation damage. The obtained microstructures were mechanically tested with subsequent metallographic and fractographic characterization. The relevant microstructural and fractographic aspects were employed in the interpretation of the mechanical behavior of the microstructures in both quasi-static (J-R curve and dynamic (Charpy impact loading regimes. A well defined relationship was determined between the elastic-plastic fracture toughness parameter J-integral and the Charpy impact energy for very most of the microstructures.

  12. Einstein His Impact on Accelerators; His Impact on the World

    CERN Document Server

    Sessler, Andrew M

    2005-01-01

    The impact of the work of Albert Einstein on accelerator physics is described. Because of the limit of time, and also because the audience knows the details, the impact is described in broad strokes. Nevertheless, it is seen how his work has affected many different aspects of accelerator physics. In the second half of the talk, Albert Einstein's impact on the world will be discussed; namely his work on world peace (including his role as a pacifist, in the atomic bomb, and in arms control) and his efforts as a humanitarian (including his efforts on social justice, anti-racism, and civil rights).

  13. Einstein: His Impact on Accelerators; His Impact on the World

    International Nuclear Information System (INIS)

    The impact of the work of Albert Einstein on accelerator physics is described. Because of the limit of time, and also because the audience knows the details, the impact is described in broad strokes. Nevertheless, it is seen how his work has affected many different aspects of accelerator physics. In the second half of the talk, Albert Einstein's impact on the world will be discussed; namely his work on world peace (including his role as a pacifist, in the atomic bomb, and in arms control) and his efforts as a humanitarian (including his efforts on social justice, anti-racism, and civil rights)

  14. 碰撞试验

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Charpy impact test modelling and local approach to fracture, Comparison of paramctric and non-paramerric mcthocis for determining injury rish, CORRELATION ANALYSIS OF AUTOMOBILE CRASH RESPONSES BASED ON WAVELET DECOMPOSITIONS, Correlation study on different bumper impact test method and predicted results, Damage behaior in ceramic plasma-coated and uncoated glass with steel-ball impact。

  15. Grain boundary chemistry and heat treatment effects on the ductile-to-brittle transition behavior of vanadium alloys

    International Nuclear Information System (INIS)

    One-third scale Charpy impact specimens of V-4Cr-4Ti were given the same heat treatments applied to equivalent specimens of V-5Cr-5Ti. Auger specimens of V-4Cr-4Ti were also heat treated with the Charpy specimens to enable grain boundary chemistry measurements. The microstructural, microchemical and Charpy impact response of V-4Cr-4Ti displayed trends similar to those observed for V-5Cr-5Ti. The results show that grain size plays an important role in determining the ductile-to-brittle transition temperature (DBTT) of these materials and that a threshold level of grain boundary segregant appears to be required to cause grain boundary embrittlement and intergranular fracture

  16. Grain boundary chemistry and heat treatment effects on the ductile-to-brittle transition behavior of vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, R.J.; Hamilton, M.L.; Li, H. [Pacific Northwest National Lab., Richland, WA (United States)

    1998-03-01

    One-third scale Charpy impact specimens of V-4Cr-4Ti were given the same heat treatments applied to equivalent specimens of V-5Cr-5Ti. Auger specimens of V-4Cr-4Ti were also heat treated with the Charpy specimens to enable grain boundary chemistry measurements. The microstructural, microchemical and Charpy impact response of V-4Cr-4Ti displayed trends similar to those observed for V-5Cr-5Ti. The results show that grain size plays an important role in determining the ductile-to-brittle transition temperature (DBTT) of these materials and that a threshold level of grain boundary segregant appears to be required to cause grain boundary embrittlement and intergranular fracture.

  17. Behind the scenes of GS: the impact of IMPACT

    CERN Multimedia

    Katarina Anthony

    2014-01-01

    Carrying out a job at CERN can be a complicated task, with coordinators reaching across departments to manage personnel, ensure safety and minimise the impact of their activities on the rest of the Laboratory.  To help coordinators with this tough task, the GS Department developed IMPACT, the platform that, since 2011, has unified CERN's major experiment, accelerator and injector coordination tools.   When planning interventions both large and small, IMPACT (the Intervention Management Planning and Coordination Tool) is the go-to gizmo on every CERN coordinator's tool belt. "IMPACT is a central repository of activity requests that standardises the way work is declared at CERN," says Benoit Daudin, GS-AIS-PM Section Leader. "If you need to intervene in any of CERN's major facilities, you need to declare this work on IMPACT. The tool will analyse the job and see whose approval is required. This could simply b...

  18. Author Impact Factor: tracking the dynamics of individual scientific impact

    Science.gov (United States)

    Pan, Raj Kumar; Fortunato, Santo

    2014-05-01

    The impact factor (IF) of scientific journals has acquired a major role in the evaluations of the output of scholars, departments and whole institutions. Typically papers appearing in journals with large values of the IF receive a high weight in such evaluations. However, at the end of the day one is interested in assessing the impact of individuals, rather than papers. Here we introduce Author Impact Factor (AIF), which is the extension of the IF to authors. The AIF of an author A in year t is the average number of citations given by papers published in year t to papers published by A in a period of Δt years before year t. Due to its intrinsic dynamic character, AIF is capable to capture trends and variations of the impact of the scientific output of scholars in time, unlike the h-index, which is a growing measure taking into account the whole career path.

  19. Author Impact Factor: tracking the dynamics of individual scientific impact

    CERN Document Server

    Pan, Raj Kumar

    2013-01-01

    The impact factor (IF) of scientific journals has acquired a major role in the evaluations of the output of scholars, departments and whole institutions. Typically papers appearing in journals with large values of the IF receive a high weight in such evaluations. However, at the end of the day one is interested in assessing the impact of individuals, rather than papers. Here we introduce Author Impact Factor (AIF), which is the extension of the IF to authors. The AIF of an author A in year $t$ is the average number of citations given by papers published in year $t$ to papers published by A in a period of $\\Delta t$ years before year $t$. Due to its intrinsic dynamic character, AIF is capable to capture trends and variations of the impact of the scientific output of scholars in time, unlike the $h$-index, which is a growing measure taking into account the whole career path.

  20. Highlighting Impact and the Impact of Highlighting: PRB Editors' Suggestions

    CERN Document Server

    Antonoyiannakis, Manolis

    2016-01-01

    Associate Editor Manolis Antonoyiannakis discusses the highlighting, as Editors' Suggestions, of a small percentage of the papers published each week. We highlight papers primarily for their importance and impact in their respective fields, or because we find them particularly interesting or elegant. It turns out that the additional layer of scrutiny involved in the selection of papers as Editors' Suggestions is associated with a significantly elevated and sustained citation impact.

  1. Lepreau 2 environmental impact statement

    International Nuclear Information System (INIS)

    Maritime Nuclear, a joint undertaking of Atomic Energy of Canada Limited and the New Brunswick Electric Power Commission, proposes to construct a second CANDU 600 MW nuclear-powered generating unit at the site of the existing Point Lepreau Generating Station, in New Brunswick. A feasibility study is now underway and guidelines issued by the Lepreau 2 Environmental Assessment Panel identified six priority issues and concerns. These are: impacts on the biological environment, impacts of radiation on humans, impacts on the socio-economic environment, monitoring, emergency planning, and decommissioning. These factors as well as a description of the site and proposed facility are described in this report

  2. 78 FR 54906 - Draft Supplemental Environmental Impact Report/Environmental Impact Statement for a Proposed...

    Science.gov (United States)

    2013-09-06

    ... Fish and Wildlife Service Draft Supplemental Environmental Impact Report/Environmental Impact Statement... Coachella Valley Conservation Commission (CVCC), has prepared a joint draft Supplemental Environmental Impact Report/Environmental Impact Statement (draft Supplemental EIR/EIS) under the...

  3. Visualizing the Impacts of Deforestation.

    Science.gov (United States)

    Fortner, Rosanne W.

    1992-01-01

    Presents two activities with investigation procedures to aid students in examining the extent and impact of biomass burning and deforestation in Brazil as an example of the global problem. Provides background information, tables, and diagrams. (five references) (MCO)

  4. Privacy Impact Assessment (PIA) Repository

    Data.gov (United States)

    Department of Veterans Affairs — This repository contains Privacy Impact Assessments (PIA) that have been vetted/approved. Section 208 of the Electronic Government Act of 2002 (E-Gov Act) requires...

  5. Drop impact on superheated surfaces

    CERN Document Server

    Tran, Tuan; Prosperetti, Andrea; Sun, Chao; Lohse, Detlef

    2011-01-01

    At impact of a liquid droplet on a smooth surface heated above the liquid's boiling point, the droplet either immediately boils when it contacts the surfaces (``contact boiling''), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (``gentle film boiling''), or both forms the Leidenfrost layer and ejects tiny droplets upward (``spraying film boiling''). We experimentally determine conditions under which impact behaviors in each regime can be realized. We show that the dimensionless maximum spreading $\\gamma$ of impacting droplets on the heated surfaces in both gentle and spraying film boiling regimes shows a universal scaling with the Weber number $\\We$ ($\\gamma\\sim\\We^{2/5}$) -- regardless of surface temperature and of liquid properties -- which is much steeper than for the impact on non-heated (hydrophilic or hydrophobic) surfaces ($\\gamma\\sim\\We^{1/4}$). We also intereferometrically measure the vapor thickness under the droplet.

  6. Distributed Impact Detection System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Automated impact detection and characterization on manned spacecraft has been an elusive goal due to the transitory nature of the detectable high-frequency signals....

  7. Broadening nanotechnology's impact on development

    Science.gov (United States)

    Beumer, Koen

    2016-05-01

    Discussions about nanotechnology and development focus on applications that directly address the needs of the world's poor. Nanotechnology can certainly make an impact in the fight against global poverty, but we need to broaden our imagination.

  8. Impact of conflict in Africa

    Directory of Open Access Journals (Sweden)

    Kathryn Touré

    2006-07-01

    Full Text Available Since independence, few African countries have beenspared violence and armed conflict. Two West Africanresearch networks recently organised an internationalcolloquium to assess the impact and develop linkagesbetween education, peace and democracy.

  9. Swept Impact Seismic Technique (SIST)

    Science.gov (United States)

    Park, C.B.; Miller, R.D.; Steeples, D.W.; Black, R.A.

    1996-01-01

    A coded seismic technique is developed that can result in a higher signal-to-noise ratio than a conventional single-pulse method does. The technique is cost-effective and time-efficient and therefore well suited for shallow-reflection surveys where high resolution and cost-effectiveness are critical. A low-power impact source transmits a few to several hundred high-frequency broad-band seismic pulses during several seconds of recording time according to a deterministic coding scheme. The coding scheme consists of a time-encoded impact sequence in which the rate of impact (cycles/s) changes linearly with time providing a broad range of impact rates. Impact times used during the decoding process are recorded on one channel of the seismograph. The coding concept combines the vibroseis swept-frequency and the Mini-Sosie random impact concepts. The swept-frequency concept greatly improves the suppression of correlation noise with much fewer impacts than normally used in the Mini-Sosie technique. The impact concept makes the technique simple and efficient in generating high-resolution seismic data especially in the presence of noise. The transfer function of the impact sequence simulates a low-cut filter with the cutoff frequency the same as the lowest impact rate. This property can be used to attenuate low-frequency ground-roll noise without using an analog low-cut filter or a spatial source (or receiver) array as is necessary with a conventional single-pulse method. Because of the discontinuous coding scheme, the decoding process is accomplished by a "shift-and-stacking" method that is much simpler and quicker than cross-correlation. The simplicity of the coding allows the mechanical design of the source to remain simple. Several different types of mechanical systems could be adapted to generate a linear impact sweep. In addition, the simplicity of the coding also allows the technique to be used with conventional acquisition systems, with only minor modifications.

  10. ECONOMIC IMPACT OF CULTURAL TOURISM

    OpenAIRE

    Zrinka Zadel; Sinisa Bogdan

    2013-01-01

    The subject of analysis in the paper is economic impact of cultural tourism and identification of the main factors which directly affect cultural tourism revenues. Most countries do not have a statistical system of monitoring and analysing individual factors of cultural tourism such as the number of arrivals of cultural tourists and consumption of cultural tourists. Therefore, it is hard to assess the economic impact of cultural tourism. In cultural tourism, cultural assets are prepared and p...

  11. Drop Impact on Superheated Surfaces

    OpenAIRE

    Tran, Tuan; Staat, Hendrik J. J.; Prosperetti, Andrea; Sun, Chao; Lohse, Detlef

    2012-01-01

    At impact of a liquid droplet on a smooth surface heated above the liquid's boiling point, the droplet either immediately boils when it contacts the surfaces (``contact boiling''), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (``gentle film boiling''), or both forms the Leidenfrost layer and ejects tiny droplets upward (``spraying film boiling''). We experimentally determine conditions under which impact behaviors in each regime can b...

  12. Collocation Impact on Team Effectiveness

    OpenAIRE

    Eccles, M.; J. Smith; Tanner, M; JP van Belle; Watt, S

    2010-01-01

    The collocation of software development teams is common, specially in agile software development environments. However little is known about the impact of collocation on the team’s effectiveness. This paper explores the impact of collocating agile software development teams on a number of team effectiveness factors. The study focused on South African software development teams and gathered data through the use of questionnaires and interviews. The key finding was that collocation has a p...

  13. Can Scientific Impact Be Predicted?

    OpenAIRE

    Dong, Yuxiao; Johnson, Reid A.; Chawla, Nitesh V

    2016-01-01

    A widely used measure of scientific impact is citations. However, due to their heavy-tailed distribution, citations are fundamentally difficult to predict. Instead, to characterize scientific impact, we address two analogous questions asked by many scientific researchers: "How will my h-index evolve over time, and which of my previously or newly published papers will contribute to it?" To answer these questions, we perform two related tasks. First, we develop a model to predict authors' futur...

  14. Immigration Wage Impacts by Origin

    OpenAIRE

    Bernt Bratsberg; Oddbjørn Raaum; Marianne Røed; Pål Schøne

    2010-01-01

    We estimate the direct partial wage effect for native workers of an immigrant-induced increase in labor supply, using longitudinal records drawn from Norwegian registers and the national skill cell approach of Borjas (2003). Our results show overall negative wage impacts for both men and women. Focusing on differential wage impacts by immigrant origin, we find that immigrant inflows from the neighboring Nordic countries have more negative wage effects than inflows from developing countries. T...

  15. Pool impacts of Leidenfrost drop

    Science.gov (United States)

    Darbois Texier, Baptiste; Maquet, Laurent; Dorbolo, Stephane; Dehandschoewercker, Eline; Pan, Zhao; Truscott, Tadd

    2015-11-01

    This work concerns the impact of a droplet made of a volatile liquid (typically HFE) on a pool of an other liquid (typically silicone oil) which temperature is above the boiling point of the drop. Depending on the properties of the two liquids and the impacting conditions, four different regimes are observed. For low impacting speeds, the droplet bounces on the surface of the bath and finally levitates above it in a Leidenfrost state. Such a regime occurs as soon as the pool temperature exceeds the boiling point of the drop. This observation means that there is no threshold in temperature for a Leidenfrost effect on a liquid surface contrary to the case of a solid substrate. For intermediate impacting velocities, the pinch-off of the surface of the pool entraps the drop in the liquid bulk. The entrapped drop is separated from the pool by a layer of its own vapour in a similar way of antibulles. For increasing impacting speeds, the vapour layer between the drop and the pool does not hold during the pinch-off event. The contact of the drop with the hot liquid provokes a sudden and intense evaporation. At very large impacting speeds, the drop rapidely contacts the pool, spreads and finally induces a hemi-spherical cavity. In the end, these four different regimes are summarized in a Froud-Weber diagram which boundaries are discussed.

  16. Effect of microstructure on the impact toughness of high strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, I.

    2014-07-01

    One of the major challenges in the development of new steel grades is to get increasingly high strength combined with a low ductile brittle transition temperature and a high upper shelf energy. This requires the appropriate microstructural design. Toughness in steels is controlled by different microstructural constituents. Some of them, like inclusions, are intrinsic while others happening at different microstructural scales relate to processing conditions. A series of empirical equations express the transition temperature as a sum of contributions from substitutional solutes, free nitrogen, carbides, pearlite, grain size and eventually precipitation strengthening. Aimed at developing a methodology that could be applied to high strength steels, microstructures with a selected degree of complexity were produced at laboratory in a Nb-microalloyed steel. As a result a model has been developed that consistently predicts the Charpy curves for ferrite-pearlite, bainitic and quenched and tempered microstructures using as input data microstructural parameters. This model becomes a good tool for microstructural design. (Author)

  17. Effect of microstructure on the impact toughness of high strength steels

    International Nuclear Information System (INIS)

    One of the major challenges in the development of new steel grades is to get increasingly high strength combined with a low ductile brittle transition temperature and a high upper shelf energy. This requires the appropriate microstructural design. Toughness in steels is controlled by different microstructural constituents. Some of them, like inclusions, are intrinsic while others happening at different microstructural scales relate to processing conditions. A series of empirical equations express the transition temperature as a sum of contributions from substitutional solutes, free nitrogen, carbides, pearlite, grain size and eventually precipitation strengthening. Aimed at developing a methodology that could be applied to high strength steels, microstructures with a selected degree of complexity were produced at laboratory in a Nb-microalloyed steel. As a result a model has been developed that consistently predicts the Charpy curves for ferrite-pearlite, bainitic and quenched and tempered microstructures using as input data microstructural parameters. This model becomes a good tool for microstructural design. (Author)

  18. 78 FR 14117 - Draft Environmental Impact Statement/Environmental Impact Report for Yolo Bypass Salmonid Habitat...

    Science.gov (United States)

    2013-03-04

    ... Bureau of Reclamation Draft Environmental Impact Statement/Environmental Impact Report for Yolo Bypass... Water Resources intend to prepare an environmental impact statement/ environmental impact report (EIS... addressed in the environmental impact statement/ environmental impact report: 1. March 14, 2013, 1:30-3:30...

  19. Designing Asteroid Impact Scenario Trajectories

    Science.gov (United States)

    Chodas, Paul

    2016-05-01

    In order to study some of the technical and geopolitical issues of dealing with an asteroid on impact trajectory, a number of hypothetical impact scenarios have been presented over the last ten years or so. These have been used, for example, at several of the Planetary Defense Conferences (PDCs), as well as in tabletop exercises with the Federal Emergency Management Agency (FEMA), along with other government agencies. The exercise at the 2015 PDC involved most of the attendees, consisted of seven distinct steps (“injects”), and with all the presentations and discussions, took up nearly 10 hours of conference time. The trajectory for the PDC15 scenario was entirely realistic, and was posted ahead of the meeting. It was made available in the NEO Program’s Horizons ephemeris service so that users could , for example, design their own deflection missions. The simulated asteroid and trajectory had to meet numerous very exacting requirements: becoming observable on the very first day of the conference, yet remaining very difficult to observe for the following 7 years, and far enough away from Earth that it was out of reach of radar until just before impact. It had to be undetectable in the past, and yet provide multiple perihelion opportunities for deflection in the future. It had to impact in a very specific region of the Earth, a specific number of years after discovery. When observations of the asteroid are simulated to generate an uncertainty region, that entire region must impact the Earth along an axis that cuts across specific regions of the Earth, the “risk corridor”. This is important because asteroid deflections generally move an asteroid impact point along this corridor. One scenario had a requirement that the asteroid pass through a keyhole several years before impact. The PDC15 scenario had an additional constraint that multiple simulated kinetic impactor missions altered the trajectory at a deflection point midway between discovery and impact

  20. ECONOMIC IMPACT OF CULTURAL TOURISM

    Directory of Open Access Journals (Sweden)

    Zrinka Zadel

    2013-12-01

    Full Text Available The subject of analysis in the paper is economic impact of cultural tourism and identification of the main factors which directly affect cultural tourism revenues. Most countries do not have a statistical system of monitoring and analysing individual factors of cultural tourism such as the number of arrivals of cultural tourists and consumption of cultural tourists. Therefore, it is hard to assess the economic impact of cultural tourism. In cultural tourism, cultural assets are prepared and placed on the tourist market, i.e. cultural resources are transformed into cultural tourism products. The main objective is fulfilling tourists' needs, and achieving positive effects which includes economic effects. Identification of the economic impact of cultural tourism is important because cultural resources have an inestimable value for the local community. Tourism valorisation should be used in order to achieve the necessary maximum effects with minimum negative impacts which tourism may leave on cultural resources. The objective of the paper is to identify the economic contribution of cultural tourism in the Republic of Croatia and to propose a model of identification of economic impact of cultural tourism.

  1. Scientific impact of large telescopes

    CERN Document Server

    Sánchez, S F

    2000-01-01

    The scientific impacts of telescopes worldwide have been compared on the basis of their contributions to (a) the 1000 most-cited astronomy papers published 1991-8 (125 from each year), and (b) the 452 astronomy papers published in Nature 1989-98. 1-m and 2-m ground-based telescopes account for \\~5% of the citations to the top-cited papers, 4-m telescopes 10%, Keck I/II 4%, sub-mm and radio telescopes 4%, HST 8%, other space telescopes 23%. The remaining citations are mainly to theoretical and review papers. The strong showing by 1-m and 2-m telescopes in the 1990s augurs well for the continued scientific impact of 4-m telescopes in the era of 8-m telescopes. The impact of individual ground-based optical telescopes is proportional to collecting area (and approximately proportional to capital cost). The impacts of the various 4-m telescopes are similar, with CFHT leading in citation counts, and WHT in Nature papers. HST has about 15 times the citation impact of a 4-m ground-based telescope, but cost >100 times ...

  2. Impact resistance of bar glasses.

    Science.gov (United States)

    Shepherd, J P; Huggett, R H; Kidner, G

    1993-12-01

    Bar glasses are often used as weapons in interpersonal violence. Violence often erupts spontaneously and assailants use objects close to hand as weapons. After an initial national Accident and Emergency Department study to identify glass designs most often implicated in interpersonal violence, the impact resistance of 1-pint beer glasses was tested in a materials laboratory with a Zwick 5102 pendulum impact tester. Both straight-sided (nonik) glasses (annealed and tempered) and handled tankards (annealed) were tested to destruction. The impact resistance of new glasses was compared with that of glasses subjected to wear. The mean impact resistance of new annealed noniks did not differ significantly although new glasses were significantly more resistant than worn glasses (p shards although the thicker bases remained intact. The mean impact resistance of new annealed noniks was 0.5 J, of worn annealed noniks 0.08 J, of tempered new noniks > 4 J, of worn tempered noniks 0.18 J, and of tankards, 1.7 J.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8263994

  3. 低C含Cu NV-F690特厚钢板的精细组织和强韧性%FINE MICROSTRUCTURE AND TOUGHNESS OF LOW CARBON COPPER CONTAINING ULTRA HIGH STRENGTH NV-F690 HEAVY STEEL PLATE

    Institute of Scientific and Technical Information of China (English)

    刘东升; 程丙贵; 陈圆圆

    2012-01-01

    本文通过板坯连铸、钢板控轧控冷(TMCP)、固溶淬火回火(QT)工业生产流程,开发低C含Cu高强韧NV-F690特厚(厚度t为80 mm)船体和海洋平台用钢板,使用SEM,EBSD和TEM分别研究了淬火(Q)态和QT态钢板的精细组织,测试了距离钢板表面t/4处(高冷却速率)和芯部t/2处(低冷却速率)的室温硬度和拉伸性能,在-60和-80℃下进行了Charpy冲击(Charpy V notch,CVN)示波实验.结果表明,淬火速率较大有利于板条组织形成和提高大角度晶界比例,t/4处的组织为板条状贝氏体(LB),板条间存在细小片状马氏体/奥氏体(M/A)组元,晶粒间大角度晶界(>15°)体积分数为67.5%;t/2处的组织为粒状贝氏体(GB)+LB.大角度晶界体积分数为63.0%;Q态下的LB具有高位错密度,但晶粒内不存在Cu析出相.经过650℃回火150 min,钢板的强韧性匹配优良,低温下呈韧性断裂,大量含Cu弥散沉淀相在基体组织内析出.t/2处的M/A组元分解为Cr-Mo碳化物,贝氏体板条宽度为0.4 μm,大角度晶界分数为62.5%; t/4处的LB板条回复,板条内存在与基体取向差较大的亚晶,大角度晶界分数提高到71.7%,板条平均宽度为0.2 μm.在-80℃下,NV-F690钢板t/4处的韧性高于t/2处的韧性.随着纤维断裂位移的增大,韧窝断裂区比例和韧窝尺寸逐渐增大,NV-F690钢低温Charpy冲击能量逐渐提高.%Advanced NV-F690 heavy steel plates for offshore structure and shipbuilding have been produced via continuous casting of the slab, thermomechanical control rolling of the plate followed by solutionizing (austenitizing), quenching and tempering (QT) steps. The present work is to reveal the microstructure evolution and evaluate the mechanical properties of 80 mm thick plates subjected to the QT process. The microstructures were characterized with SEM, EBSD and TEM. At quarter thickness (f/4) where the cooling rate was rapid, the as quenched microstructures consist of mainly lath

  4. Environmental impact of wind energy

    Science.gov (United States)

    Mann, J.; Teilmann, J.

    2013-09-01

    One purpose of wind turbines is to provide pollution-free electric power at a reasonable price in an environmentally sound way. In this focus issue the latest research on the environmental impact of wind farms is presented. Offshore wind farms affect the marine fauna in both positive and negative ways. For example, some farms are safe havens for porpoises while other farms show fewer harbor porpoises even after ten years. Atmospheric computer experiments are carried out to investigate the possible impact and resource of future massive installations of wind turbines. The following questions are treated. What is the global capacity for energy production by the wind? Will the added turbulence and reduced wind speeds generated by massive wind farms cool or heat the surface? Can wind farms affect precipitation? It is also shown through life-cycle analysis how wind energy can reduce the atmospheric emission of eight air pollutants. Finally, noise generation and its impact on humans are studied.

  5. SCIX IMPACT ON DWPF CPC

    Energy Technology Data Exchange (ETDEWEB)

    Koopman, D.

    2011-07-14

    A program was conducted to systematically evaluate potential impacts of the proposed Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) Chemical Processing Cell (CPC). The program involved a series of interrelated tasks. Past studies of the impact of crystalline silicotitanate (CST) and monosodium titanate (MST) on DWPF were reviewed. Paper studies and material balance calculations were used to establish reasonable bounding levels of CST and MST in sludge. Following the paper studies, Sludge Batch 10 (SB10) simulant was modified to have both bounding and intermediate levels of MST and ground CST. The SCIX flow sheet includes grinding of the CST which is larger than DWPF frit when not ground. Nominal ground CST was not yet available, therefore a similar CST ground previously in Savannah River National Laboratory (SRNL) was used. It was believed that this CST was over ground and that it would bound the impact of nominal CST on sludge slurry properties. Lab-scale simulations of the DWPF CPC were conducted using SB10 simulants with no, intermediate, and bounding levels of CST and MST. Tests included both the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles. Simulations were performed at high and low acid stoichiometry. A demonstration of the extended CPC flowsheet was made that included streams from the site interim salt processing operations. A simulation using irradiated CST and MST was also completed. An extensive set of rheological measurements was made to search for potential adverse consequences of CST and MST and slurry rheology in the CPC. The SCIX CPC impact program was conducted in parallel with a program to evaluate the impact of SCIX on the final DWPF glass waste form and on the DWPF melter throughput. The studies must be considered together when evaluating the full impact of SCIX on DWPF. Due to the fact that the alternant flowsheet for DWPF has not been selected, this study did not

  6. Environmental impact assessment screening tool

    International Nuclear Information System (INIS)

    An environmental assessment and impact planning software, SCREENER, was tested at a pilot project at the Cameco site (Port Hope). SCREENER was used to screen the impacts of a new construction project in accordance with the process and reporting requirements laid out in the Canadian Environmental Assessment Act. The software test concentrated on the activities that are directly involved with the structure construction and site preparation activities. In addition, a two and one half day training course was given to three AECB staff using the test case as a hands on example. The conclusion of this project is that an automated tool such as SCREENER (or Calyx, the new generation of environmental assessment tools from ESSA Software Ltd.), will help the AECB to standardize the approach to environmental assessment, assist in project planning, and save resources in the screening process. The new approach could allow to allocate AECB limited resources to the detailed assessments required for maximum impact activities

  7. Drop impact on a fiber

    Science.gov (United States)

    Kim, Sung-Gil; Kim, Wonjung

    2016-04-01

    We present the results of a combined experimental and theoretical investigation of drop impact on a thin fiber. Using high-speed videography, we analyze the dynamics of droplet collision with a fiber. Based on the systematic experiments, we identify three outcomes of collision: capturing, single drop falling, and splitting. The outcomes are presented in a regime map, where the regime boundaries are explained through a scale analysis of forces. We also measure the liquid retention on the fiber after the droplet impact. By considering a liquid film on the fiber, we develop a mechanical model that predicts the residual water mass. Our model reveals that the residual mass depends critically on the fiber thickness and less on the impact speed. Our study can be extended to predicting the remaining droplet, critical problems in air filtration, water collection, and fiber coating.

  8. Impact, productivity, and scientific excellence

    CERN Document Server

    Kaur, Jasleen; Menczer, Filippo; Flammini, Alessandro; Radicchi, Filippo

    2014-01-01

    Citation metrics are becoming pervasive in the quantitative evaluation of scholars, journals and institutions. More then ever before, hiring, promotion, and funding decisions rely on a variety of impact metrics that cannot disentangle quality from productivity, and are biased by factors such as discipline and academic age. Biases affecting the evaluation of single papers are compounded when one aggregates citation-based metrics across an entire publication record. It is not trivial to compare the quality of two scholars that during their careers have published at different rates in different disciplines in different periods of time. We propose a novel solution based on the generation of a statistical baseline specifically tailored on the academic profile of each researcher. By decoupling productivity and impact, our method can determine whether a certain level of impact can be explained by productivity alone, or additional ingredients of scientific excellence are necessary. The method is flexible enough to al...

  9. Stable and unstable crack growth in pressure vessel models

    International Nuclear Information System (INIS)

    Three identical steel pressure vessels with 254-mm (10-in.) dia, 38-mm (1.5-in.) wall thicknesses and long, deep machined and sharpened axially oriented flaws were tested at three different temperatures. The vessels were assembled by electron-beam welding cylindrical sections with substantially different toughnesses due to different heat treatments. Crack extension initiated in relatively brittle sections, and the cracks extended both stably and unstably, depending on test temperature, toward the tougher sections where crack arrest did and did not occur. Charpy impact specimens and both slow-bend and dynamic precracked Charpy specimens were used for material characterization. The behavior of the vessels is described and related to the Charpy data

  10. Molecular dynamics simulation of impact test

    Energy Technology Data Exchange (ETDEWEB)

    Akahoshi, Y. [Kyushu Inst. of Tech., Kitakyushu, Fukuoka (Japan); Schmauder, S.; Ludwig, M. [Stuttgart Univ. (Germany). Staatliche Materialpruefungsanstalt

    1998-11-01

    This paper describes an impact test by molecular dynamics (MD) simulation to evaluate embrittlement of bcc Fe at different temperatures. A new impact test model is developed for MD simulation. The typical fracture behaviors show transition from brittle to ductile fracture, and a history of the impact loads also demonstrates its transition. We conclude that the impact test by MD could be feasible. (orig.)

  11. E-IMPACT - A ROBUST HAZARD-BASED ENVIRONMENTAL IMPACT ASSESSMENT APPROACH FOR PROCESS INDUSTRIES

    OpenAIRE

    KHANDOKER A. HOSSAIN; FAISAL KHAN; KELLY HAWBOLDT

    2008-01-01

    This paper proposes a hazard-based environmental impact assessment approach (E-Impact), for evaluating the environmental impact during process design and retrofit stages. E-Impact replaces the normalisation step of the conventional impact assessment phase. This approach compares the impact scores for different options and assigns a relative score to each option. This eliminates the complexity of the normalisation step in the evaluation phase. The applicability of the E-Impact has been illustr...

  12. SPH Simulation of Hypervelocity Impacts

    Institute of Scientific and Technical Information of China (English)

    李金柱; 张庆明; 龙仁容

    2004-01-01

    The smooth particle hydrodynamics (SPH) method is a very important tool to resolve hypervelocity problems. The basic principle of SPH method and how to generate a proper SPH mesh is described. The results of SPH simulations of hypervelocity impacts on thin or thick aluminum plates, performed by using the LS-DYNA 3D computer code, are also reported. The forming process and composition of the debris clouds simulated are identical with the experiment results. It can be concluded that the simulation is reasonable and SPH method is an ideal method for hypervelocity impact simulation.

  13. The Selby Coalfield impact study

    Energy Technology Data Exchange (ETDEWEB)

    Shutt, J.; Henderson, R.; Kumi-Ampofo, F.; Thursfield, D. [Leeds Metropolitan University, Leeds (United Kingdom). Leeds Business School

    2002-07-01

    This report considers the likely economic and social impacts. It sets out proposals for the establishment of a Selby Mines Closure Task Force. There is a need to mitigate the economic and social impacts of the potential closure and to develop a re-invigorated focus on a sub-regional skills, re-training and regeneration and planning programme co-ordinating the wide range of stakeholders who will need to be involved. 26 refs., 4 figs., 15 tabs. 12 maps., 9 apps.

  14. Introducing Life Cycle Impact Assessment

    DEFF Research Database (Denmark)

    Hauschild, Michael Zwicky; Huijbregts, Mark AJ

    2015-01-01

    methodology projects and presents the international scientific discussions and methodological consensus attempts in consecutive working groups under the auspices of the Society of Environmental Toxicology and Chemistry (SETAC) as well as the UNEP/ SETAC Life Cycle Initiative, and the (almost) parallel......This chapter serves as an introduction to the presentation of the many aspects of life cycle impact assessment (LCIA) in this volume of the book series ‘LCA Compendium’. It starts with a brief historical overview of the development of life cycle impact assessment driven by numerous national LCIA...

  15. ONTARIO GRAPE PRODUCTION ECONOMIC IMPACT

    OpenAIRE

    Grier, Kevin; Martin, Larry J.; Stiefelmeyer, Kate

    2000-01-01

    This report was undertaken in order to measure the economic impacts of the grape industry on the Ontario economy and the impacts of maintaining the Wine Content Act at the 30% level. It will also provide an estimate of the benefits to grape growers and Ontario of increasing the requirements of the Wine Content Act to 75%. Specifically, the objectives are: 1. To determine the current contribution of the processing grape industry to the economy of Ontario. 2. To estimate the economic effects of...

  16. Lifetime environmental impact of buildings

    CERN Document Server

    Mequignon, Marc

    2014-01-01

    This work discusses the impact of the life of buildings on? sustainable development methods.?The study of the lifespan of the building is used to assess and?manage the environmental impacts associated?with all the stages of a product's life, from raw material extraction?through to repair, maintenance and?? 'end of life' scenarios. While several papers have discussed thegreenhouse gas emissions of buildings,?less research has been done on how these are affected by the lifespan?of the building. This book serves to?highlight the pertinence of this factor and contributes to providing?new ideas on

  17. Columbia River Impact Evaluation Plan

    International Nuclear Information System (INIS)

    A preliminary impact evaluation was conducted to assess the adequacy of existing data and proposed data collection programs for evaluating cumulative health and environmental impacts to the Columbia River due to past practices at the Hanford Site. The results of this evaluation were used to develop this plan to ensure collection of sufficient data for adequate characterization of the Columbia River along the 100 Area for CERCLA purposes. The evaluation used to develop the plan is not a risk assessment; the plan presented here is only a mechanism to collect additional data to support a future risk assessment

  18. Large meteoroid's impact damage: review of available impact hazard simulators

    Science.gov (United States)

    Moreno-Ibáñez, M.; Gritsevich, M.; Trigo-Rodríguez, J. M.

    2016-01-01

    The damage caused by meter-sized meteoroids encountering the Earth is expected to be severe. Meteor-sized objects in heliocentric orbits can release energies higher than 108 J either in the upper atmosphere through an energetic airblast or, if reaching the surface, their impact may create a crater, provoke an earthquake or start up a tsunami. A limited variety of cases has been observed in the recent past (e.g. Tunguska, Carancas or Chelyabinsk). Hence, our knowledge has to be constrained with the help of theoretical studies and numerical simulations. There are several simulation programs which aim to forecast the impact consequences of such events. We have tested them using the recent case of the Chelyabinsk superbolide. Particularly, Chelyabinsk belongs to the ten to hundred meter-sized objects which constitute the main source of risk to Earth given the current difficulty in detecting them in advance. Furthermore, it was a detailed documented case, thus allowing us to properly check the accuracy of the studied simulators. As we present, these open simulators provide a first approximation of the impact consequences. However, all of them fail to accurately determine the caused damage. We explain the observed discrepancies between the observed and simulated consequences with the following consideration. The large amount of unknown properties of the potential impacting meteoroid, the atmospheric conditions, the flight dynamics and the uncertainty in the impact point itself hinder any modelling task. This difficulty can be partially overcome by reducing the number of unknowns using dimensional analysis and scaling laws. Despite the description of physical processes associated with atmospheric entry could be still further improved, we conclude that such approach would significantly improve the efficiency of the simulators.

  19. Mechanical vs. informational components of price impact

    Science.gov (United States)

    Doyne Farmer, J.; Zamani, N.

    2007-01-01

    We study the problem of what causes prices to change. It is well known that trading impacts prices — orders to buy drive the price up, and orders to sell drive it down. We introduce a means of decomposing the total impact of trading into two components, defining the mechanical impact of a trading order as the change in future prices in the absence of any future changes in decision making, and the informational impact as the remainder of the total impact once mechanical impact is removed. This decomposition is performed using order book data from the London Stock Exchange. The average mechanical impact of a market order decays to zero as a function of time, at an asymptotic rate that is consistent with a power law with an exponent of roughly 1.7. In contrast the average informational impact builds to approach a constant value. Initially the impact is entirely mechanical, and is about half as big as the asymptotic informational impact. The size of the informational impact is positively correlated to mechanical impact. For cases where the mechanical impact is zero for all times, we find that the informational impact is negative, i.e. buy market orders that have no mechanical impact at all generate strong negative price responses.

  20. Health in social impact assessment

    NARCIS (Netherlands)

    den Broeder, Lea; Vanclay, Frank; Fehr, Rainer; Viliani, Francesca; Nowacki, Julia; Martuzzi, Marco

    2014-01-01

    SIA developed alongside EIA in the early 1970s as a mechanism to consider the social impacts of planned interventions. The early understanding tended to limit the practical application of SIA to the project level, usually within the context of regulatory frameworks, and primarily considered only the

  1. Monitoring study and impact assessment

    OpenAIRE

    Budidarsono, Suseno; Rahmanulloh, Arif

    2008-01-01

    Report on the progress of socio-economic objective of LTRP 5 in Indonesia. The objectives were: (1) Identify vegetable cultivation technology on agroforestry system that socially acceptable, economically feasible, and affordable; (2) Provide information on the level adoption of vegetable cultivation technology in agroforestry system and (3)Assess impacts of technology adoption on farmers' incomes.

  2. Aluminum honeycomb impact limiter study

    Energy Technology Data Exchange (ETDEWEB)

    Yaksh, M.C.; Thompson, T.C. (Nuclear Assurance Corp., Norcross, GA (United States)); Nickell, R.E. (Applied Science and Technology, Inc., Poway, CA (United States))

    1991-07-01

    Design requirements for a cask transporting radioactive materials must include the condition of the 30-foot free fall of the cask onto an unyielding surface. To reduce the deceleration loads to a tolerable level for all the components of the cask, a component (impact limiter) is designed to absorb the kinetic energy. The material, shape, and method of attachment of the impact limiter to the cask body comprises the design of the impact limiter. The impact limiter material of interest is honeycomb aluminum, and the particular design examined was for the NAC Legal Weight Truck cask (NAC-LWT) for spent fuel from light water reactors. The NAC-LWT has a design weight of 52,000 pounds, and it has a nominal length of 200 inches. The report describes the numerical calculations embodied in the FADE program to determine the accelerations and crush strain resulting from an arbitrary height and angle of orientation. Since the program serves as a design tool, static tests are performed to assess the effect of the shell containing the honeycomb aluminum. The static tests and their results are contained in the study. The static tests are used to demonstrate for licensing purposes the level of accelerations imposed on the cask during a 30-foot drop. 3 refs., 41 figs., 15 tabs.

  3. Economic impact of GM crops

    Science.gov (United States)

    Brookes, Graham; Barfoot, Peter

    2014-01-01

    A key part of any assessment of the global value of crop biotechnology in agriculture is an examination of its economic impact at the farm level. This paper follows earlier annual studies which examined economic impacts on yields, key costs of production, direct farm income and effects, and impacts on the production base of the four main crops of soybeans, corn, cotton and canola. The commercialization of genetically modified (GM) crops has continued to occur at a rapid rate, with important changes in both the overall level of adoption and impact occurring in 2012. This annual updated analysis shows that there have been very significant net economic benefits at the farm level amounting to $18.8 billion in 2012 and $116.6 billion for the 17-year period (in nominal terms). These economic gains have been divided roughly 50% each to farmers in developed and developing countries. GM technology have also made important contributions to increasing global production levels of the four main crops, having added 122 million tonnes and 230 million tonnes respectively, to the global production of soybeans and maize since the introduction of the technology in the mid-1990s. PMID:24637520

  4. Collocation Impact on Team Effectiveness

    Directory of Open Access Journals (Sweden)

    M Eccles

    2010-11-01

    Full Text Available The collocation of software development teams is common, specially in agile software development environments. However little is known about the impact of collocation on the team’s effectiveness. This paper explores the impact of collocating agile software development teams on a number of team effectiveness factors. The study focused on South African software development teams and gathered data through the use of questionnaires and interviews. The key finding was that collocation has a positive impact on a number of team effectiveness factors which can be categorised under team composition, team support, team management and structure and team communication. Some of the negative impact collocation had on team effectiveness relate to the fact that team members perceived that less emphasis was placed on roles, that morale of the group was influenced by individuals, and that collocation was invasive, reduced level of privacy and increased frequency of interruptions. Overall through it is proposed that companies should consider collocating their agile software development teams, as collocation might leverage overall team effectiveness.

  5. Missile impact on structural members

    International Nuclear Information System (INIS)

    In this paper, a unified methodology will be developed to evaluate impact effects of hard missiles on reinforced concrete and steel members including plates/walls and beams. The solution will be investigated based on two ultimate limit states: local perforation and structural collapse of flexible plates and beams

  6. Has occupy had an impact?

    OpenAIRE

    Martell, Luke

    2012-01-01

    September 2012 was the first birthday of Occupy Wall Street. It returned to Manhattan to mark the occasion. In the UK, occupations kicked off in the student sit-ins of winter 2010. Further afield street protest spread from Spain across Europe to North America. But is it right to say that in the end the Occupy movement had no impact?

  7. A Scale of Mobbing Impacts

    Science.gov (United States)

    Yaman, Erkan

    2012-01-01

    The aim of this research was to develop the Mobbing Impacts Scale and to examine its validity and reliability analyses. The sample of study consisted of 509 teachers from Sakarya. In this study construct validity, internal consistency, test-retest reliabilities and item analysis of the scale were examined. As a result of factor analysis for…

  8. Employment Impact of Electronic Business.

    Science.gov (United States)

    Hecker, Daniel E.

    2001-01-01

    Electronic business is stimulating employment in some sectors across industries, such as computer-related and customer service occupations, and diminishing employment in others, such as administrative support and marketing/sales. Similarly, employment impacts will vary by industry. (Contains 56 notes and references.) (SK)

  9. Drop Impact on Superheated Surfaces

    NARCIS (Netherlands)

    Tran, A.T.; Staat, H.J.J.; Prosperetti, A.; Sun, C.; Lohse, D.

    2012-01-01

    At the impact of a liquid droplet on a smooth surface heated above the liquid’s boiling point, the droplet either immediately boils when it contacts the surface (“contact boiling”), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (“gentle film

  10. CEO Narcissism: Measurement and Impact

    NARCIS (Netherlands)

    J.A. Rijsenbilt (Antoinette)

    2011-01-01

    textabstractThis research describes the objective measurement of CEO narcissism and its impact on organizational outcomes. Narcissism forms an essential element for effective leadership and is as such an important personal characteristic for CEOs. CEO narcissism can be measured by investigating fi

  11. Impact on Learning Award Winners.

    Science.gov (United States)

    School Planning & Management, 2000

    2000-01-01

    Presents awardees of the School Planning & Management magazine's third annual "Impact on Learning Award" given to architectural firms whose K-12 school facilities have solved real-world problems through design, engineering, and technology solutions. Each selection presents the design challenge faced and its solution along with project details. (GR)

  12. Review of submissions: competition impacts

    NARCIS (Netherlands)

    G. Burghouwt; W. de Wit

    2015-01-01

    The Airports Commission requested ITF/SEO to provide technical assistance with analysing responses that pertain to the previous work undertaken by the ITF/SEO. This report assesses the submissions by the stakeholders in relation to competition impacts and compares them with the ITF/SEO results and t

  13. Open Access Makes an Impact

    Directory of Open Access Journals (Sweden)

    Alexander Böker

    2013-07-01

    Full Text Available Polymers published its first issue in December 2009. At that time, the editorial board and publisher were determined to lead the journal to become another MDPI success story, proving that open access publishing and high quality publications, ensured by a rigorous peer-review procedure, followed by fast publication of accepted manuscripts can be achieved. Three and a half years later, after more than 153,000 article downloads in 2012, the journal received its first impact factor (2012 JCR IF: 1.687. Today, Polymers is proud to be the number one open access journal in the category of “Polymer Science”. In order to achieve this, we relied on an editorial board with well-known members from the polymer community, a professional staff and a vision that there is room alongside the established “high impact” journals for publishing science. Recently, the editor in chief of Science, Bruce Alberts, wrote an editorial [1] in favor of the San Francisco Declaration on Research Assessment (DORA, which states that the impact factor must not be used as “a surrogate measure of the quality of individual research articles [2]”. Even though the impact factor certainly is so far the best available measure of the quality of a journal and its impact on the scientific community, when it comes to the single manuscripts published, “there is still no other way to evaluate the quality of scientific papers, but to read them [3]”. Therefore, Polymers celebrates its first impact factor with an appropriate critical distance towards bibliometric data and feels encouraged to continue on the chosen path. With this in mind, I encourage you, our readers, to continuously evaluate the scientific quality of the articles published in Polymers by reading, discussing and citing them.

  14. Experimental study on impact disruption of porous asteroids: Effects of oblique impact and multiple collisions on impact strength

    Science.gov (United States)

    Yasui, Minami; Takano, Shota; Matsue, Kazuma; Arakawa, Masahiko

    2015-08-01

    Most of asteroids would have pores and a plenty of pre-cracks in their interiors, and the pre-cracks could be formed by multiple impacts at various impact angles. Porosity and pre-cracks are important physical properties controlling the impact strength. Okamoto and Arakawa (2009) did impact experiments of porous gypsum spheres to obtain the impact strength of porous asteroids, but they carried out only single impact experiments on the same target at head-on. In this study, we conducted oblique impact and multiple impacts on porous gypsum and examined the effects of impact angle and pre-cracks on the impact strength.We carried out impact experiments by using the one-stage He gas gun and the two-stage H2 gas gun at Kobe University. The impact velocities were 3 km/s (high-vi). Targets were porous gypsum spheres with the porosity of 55% and the diameters of 7 or 12 cm. The projectiles were a porous gypsum sphere with the diameter of 2.5 cm at low-vi or a polycarbonate sphere with the diameter of 4.7 cm at high-vi. The impact angle changed from 15° to 90°, and the projectile was impacted on the same target for 2-15 times. The impact phenomena were observed by a high-speed digital video camera to measure the fragment velocities.The oblique impact experiments showed that the impact strength did not depend on the impact angle θ between 45° and 90°, and obtained to be ~2000 J/kg, while it drastically changed at the θ from 15° to 30°. We reanalyzed our results by using the effective energy density defined as Qsin2θ, where Q is the energy density, and found that most of the results were consistent with the results of head-on impacts. The multiple impacts showed that the impact strength of pre-impacted targets was larger than that of intact targets in the case of low-vi. This might be caused by the compaction of the target surface. In the case of high-vi, the impact strength of pre-impacted targets was smaller than that of intact targets. This is because many cracks

  15. [The "impact factor" and the impact of medical journals].

    Science.gov (United States)

    Reyes, H

    1998-02-01

    Original articles published in scientific journals are important parameters for committees when they evaluate academic promotions or research grant applications. The analysis usually tries to give each paper a qualitative/quantitative assessment. An article's citation by others is accepted as a fair estimate of the value assigned to its originality and importance. A main determinant of every citation index is the international relevance attained by the journal where the article appeared. The "impact factor" of journals enlisted in the mainstream literature, as defined by the Journal Citation Reports (ISI), is being used by many assessors worldwide. But this index appears to be an unfair unit of measurement for journals that, although included in the main international data bases, are published in non-English languages. Furthermore, some local journals that are not enlisted by the Institute for Scientific Information apply external peer review to select their publications. In contrast, those same journals may have great relevance for their contributing authors and a high impact in their readers. The Editor's proposal is to classify original articles published in biomedical sciences, clinical medicine and public health topics using a three steps scale: a low score to articles published in local journals that use the peer review system, even though they were not enlisted in international data bases; a higher score to articles published in journals included in the mainstream literature, without considering their "impact factors" as differential values; and the highest score to articles published in journals recognized as international leaders in biomedicine, general medicine or in the subspecialties. Therefore, mainstream journals published in non-English languages would not be discriminated from other journals having higher "impact factors" mainly due to their use of the English language.

  16. Ageing phenomena in ULCB-NiCu steels

    International Nuclear Information System (INIS)

    Effect od ageing time and temperature on microstructure development, precipitation of εCu, advancement of recrystallization process and their influence on yield strength and fracture toughness properties KIC as well as high Charpy V impact energy CVN = 84 J at 120oC of ultra low carbon bainitic copper bearing steels have ben discussed. (author)

  17. Weldability investigation steel P 91 by weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2015-07-01

    Full Text Available This paper elaborates results of hardness and impact energy of thermal cycle simulated specimens of high-alloy steel P 91 and their dependence on cooling time from 800 to 500 °C. Results were obtained by measuring hardness HV 1 and by experimental testing of Charpy notched specimens. Metallographic analysis of samples was performed on scanning electronic microscope.

  18. Impact Amber, Popcorn, and Pathology: The Biology of Impact Melt Breccias and Implications for Astrobiology

    Science.gov (United States)

    Harris, R. S.; Schultz, P. H.

    2007-03-01

    We present evidence that superheated impact melts can trap and preserve both floral and faunal remains forming "impact amber." We discuss terrestrial occurrences of impact amber and the strategy it suggests in searching for evidence of past life on other

  19. Edge impact modeling on stiffened composite structures

    OpenAIRE

    Ostré, Benjamin; Bouvet, Christophe; Minot, Clément; Aboissière, Jacky

    2015-01-01

    Finite Element Analysis of low velocity/low energy edge impact has been carried out on carbon fiber reinforced plastic structure. Edge impact experimental results were then compared to the numerical ‘‘Discrete Ply Model’’ in order to simulate the edge impact damage. This edge impact model is inspired to out-of-plan impact model on a laminate plate with addition of new friction and crushing behaviors. From a qualitative and quantitative point of view, this edge impact model reveals a relati...

  20. Mechanical vs. informational components of price impact

    OpenAIRE

    J. Doyne Farmer; Neda Zamani

    2006-01-01

    We study the problem of what causes prices to change. We define the mechanical impact of a trading order as the change in future prices in the absence of any future changes in decision making, and its it informational impact as the remainder of the total impact once mechanical impact is removed. We introduce a method of measuring mechanical impact and apply it to order book data from the London Stock Exchange. The average mechanical impact of a market order decays to zero as a function of tim...

  1. Regression Verification Using Impact Summaries

    Science.gov (United States)

    Backes, John; Person, Suzette J.; Rungta, Neha; Thachuk, Oksana

    2013-01-01

    Regression verification techniques are used to prove equivalence of syntactically similar programs. Checking equivalence of large programs, however, can be computationally expensive. Existing regression verification techniques rely on abstraction and decomposition techniques to reduce the computational effort of checking equivalence of the entire program. These techniques are sound but not complete. In this work, we propose a novel approach to improve scalability of regression verification by classifying the program behaviors generated during symbolic execution as either impacted or unimpacted. Our technique uses a combination of static analysis and symbolic execution to generate summaries of impacted program behaviors. The impact summaries are then checked for equivalence using an o-the-shelf decision procedure. We prove that our approach is both sound and complete for sequential programs, with respect to the depth bound of symbolic execution. Our evaluation on a set of sequential C artifacts shows that reducing the size of the summaries can help reduce the cost of software equivalence checking. Various reduction, abstraction, and compositional techniques have been developed to help scale software verification techniques to industrial-sized systems. Although such techniques have greatly increased the size and complexity of systems that can be checked, analysis of large software systems remains costly. Regression analysis techniques, e.g., regression testing [16], regression model checking [22], and regression verification [19], restrict the scope of the analysis by leveraging the differences between program versions. These techniques are based on the idea that if code is checked early in development, then subsequent versions can be checked against a prior (checked) version, leveraging the results of the previous analysis to reduce analysis cost of the current version. Regression verification addresses the problem of proving equivalence of closely related program

  2. Assessment of Traffic Noise Impacts

    DEFF Research Database (Denmark)

    Rich, Jeppe Husted; Nielsen, Otto Anker

    2004-01-01

    the true social benefit of infrastructure plans. The paper presents a noise assessment model for the Copenhagen region, which brings together GIS technology and non-linear hedonic regression models to reveal the implicit costs of traffic noise measured as the marginal percentage loss in property values...... with respect to the decibel traffic noise. The model distinguishes between houses and apartments and shows that the ability to include refined accessibility variables have significant impact on estimated prices.......A steady growth in traffic intensities in most urban areas throughout the world has forced planners and politicians to seriously consider the resulting environmental impact, such as traffic noise, accidents and air pollution. The assessment of such negative factors is needed in order to reveal...

  3. Venus - Lavinia Region Impact Craters

    Science.gov (United States)

    1990-01-01

    Three large meteorite impact craters, with diameters that range from 37 to 50 kilometers (23 to 31 miles), are seen in this image of the Lavinia region of Venus. The image is centered at 27 degrees south latitude and 339 degrees east longitude (longitude on Venus is measured from 0 degrees to 360 degrees east), and covers an area 550 kilometers (342 miles) wide by about 500 kilometers (311 miles) long. Situated in a region of fractured plains, the craters show many features typical of meteorite impact craters, including rough (bright) material around the rim, terraced inner walls and central peaks. Numerous domes, probably caused by volcanic activity, are seen in the southeastern corner of the mosaic. The domes range in diameter from 1 to 12 kilometers (0.6 to 7 miles). Some of the domes have central pits that are typical of some types of volcanoes. North is at the top of the image.

  4. Climate Impact of Solar Variability

    Science.gov (United States)

    Schatten, Kenneth H. (Editor); Arking, Albert (Editor)

    1990-01-01

    The conference on The Climate Impact of Solar Variability, was held at Goddard Space Flight Center from April 24 to 27, 1990. In recent years they developed a renewed interest in the potential effects of increasing greenhouse gases on climate. Carbon dioxide, methane, nitrous oxide, and the chlorofluorocarbons have been increasing at rates that could significantly change climate. There is considerable uncertainty over the magnitude of this anthropogenic change. The climate system is very complex, with feedback processes that are not fully understood. Moreover, there are two sources of natural climate variability (volcanic aerosols and solar variability) added to the anthropogenic changes which may confuse our interpretation of the observed temperature record. Thus, if we could understand the climatic impact of the natural variability, it would aid our interpretation and understanding of man-made climate changes.

  5. Environmental impact of wind energy

    DEFF Research Database (Denmark)

    Mann, Jakob; Teilmann, Jonas

    2013-01-01

    One purpose of wind turbines is to provide pollution-free electric power at a reasonable price in an environmentally sound way. In this focus issue the latest research on the environmental impact of wind farms is presented. Offshore wind farms affect the marine fauna in both positive and negative...... are treated. What is the global capacity for energy production by the wind? Will the added turbulence and reduced wind speeds generated by massive wind farms cool or heat the surface? Can wind farms affect precipitation? It is also shown through life-cycle analysis how wind energy can reduce the atmospheric...... emission of eight air pollutants. Finally, noise generation and its impact on humans are studied....

  6. Atomic Ionization by Electron Impact

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The field of atomic ionization by electron impact is several decades old. In that period of time, significant progress has been made in several aspects of the problem and we have learned a lot about ionizing collisions as a result of this work. Over the years, both the experiments and theories have improved dramatically. Experiments are now able to measure absolute triple differential cross sections for both in-plane or out-of-plane geometries. Theories have been getting better and better at including all the 3-body interactions in the wavefunction for the system. However, during the history of the field, experiment has been ahead of theory and it is just very recently that theory has started to catch up. In this paper, we will show that theory is now able to accurately predict the results of electron impact ionization of hydrogen for intermediate and higher energies.

  7. Impact of Emotion on Consciousness

    DEFF Research Database (Denmark)

    Thomsen, Kristine Rømer; Lou, Hans Olav Christensen; Jønsson, Morten;

    2011-01-01

    showed that participants were more confident and accurate when consciously seeing happy versus sad/neutral faces and words. When stimuli were presented subliminally, we found no effect of emotion. To investigate the neural basis of this impact of emotion, we recorded local field potentials (LFPs...... and consciousness. Here we tested the impact of emotion on conscious experience, and directly investigated the role of the ACC. We used a masked paradigm that measures conscious reportability in terms of subjective confidence and objective accuracy in identifying the briefly presented stimulus in a forced......) directly in the ACC in a chronic pain patient. Behavioural findings were replicated: the patient was more confident and accurate when (consciously) seeing happy versus sad faces, while no effect was seen in subliminal trials. Mirroring behavioural findings, we found significant differences in the LFPs...

  8. Impact study on electromagnetic spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Lamarre, S.; Levert, M. [Canadian Broadcasting Corporation, Montreal, PQ (Canada)

    2007-07-01

    This presentation described the signal degradation that wind turbines can cause to the existing transmission system at the Canadian Broadcasting Corporation. Vulnerable services include analogue television, digital television and AM radio. Signal quality measurements were taken at wind farms in order to quantify and qualify this degradation. An impact study on the electromagnetic spectrum considered wind turbine size, material, orientation, number, location and blade rotation speed as well as the frequency, modulation and propagation of transmitters and receivers. Mitigation measures to reduce or eliminate degradation of signals in impacted zones include: improve the directivity of the receiving antenna; replace the off-air reception with an alternative such as satellite or cable; relocate the receiving antenna; relocate the transmitter site; or relocate the problematic wind turbines. It was noted that not all mitigation measures are always efficient nor economically feasible. It was suggested that a coordination process should be created to promote exchange between wind energy developers and spectrum users. figs.

  9. Mechanical vs. informational components of price impact

    CERN Document Server

    Farmer, J D; Zamani, Neda

    2006-01-01

    We study the problem of what causes prices to change. We define the mechanical impact of a trading order as the change in future prices in the absence of any future changes in decision making, and its it informational impact as the remainder of the total impact once mechanical impact is removed. We introduce a method of measuring mechanical impact and apply it to order book data from the London Stock Exchange. The average mechanical impact of a market order decays to zero as a function of time, at an asymptotic rate that is consistent with a power law with an exponent of roughly 1.7. In contrast the average informational impact builds to approach a constant value. Initially the impact is entirely mechanical, and is about half as big as the asymptotic informational impact. The size of the informational impact is positively correlated to mechanical impact. For cases where the mechanical impact is zero for all times, we find that the informational impact is negative, i.e. buy market orders that have no mechanica...

  10. Impact significance determination-Pushing the boundaries

    International Nuclear Information System (INIS)

    Impact significance determination practice tends to be highly variable. Too often insufficient consideration is given to good practice insights. Also, impact significance determinations are frequently narrowly defined addressing, for example, only individual, negative impacts, focusing on bio-physical impacts, and not seeking to integrate either the Precautionary Principle or sustainability. This article seeks to extend the boundaries of impact significance determination practice by providing an overview of good general impact significance practices, together with stakeholder roles and potential methods for addressing significance determination challenges. Relevant thresholds, criteria, contextual considerations and support methods are also highlighted. The analysis is then extended to address how impact significance determination practices change for positive as compared with negative impacts, for cumulative as compared with individual impacts, for socio-economic as compared with bio-physical impacts, when the Precautionary Principle is integrated into the process, and when sustainability contributions drive the EIA process and related impact significance determinations. These refinements can assist EIA practitioners in ensuring that the scope and nature of impact significance determinations reflect the broadened scope of emerging EIA requirements and practices. Suggestions are included for further refining and testing of the proposed changes to impact significance determination practice

  11. Emission Impacts of Electric Vehicles

    OpenAIRE

    Wang, Quanlu; DeLuchi, Mark A.; Sperling, Daniel

    1990-01-01

    Alternative vehicular fuels are proposed as a strategy to reduce urban air pollution. In this paper, we analyze the emission impacts of electric vehicles in California for two target years, 1995 and 2010. We consider a range of assumptions regarding electricity consumption of electric vehicles, emission control technologies for power plants, and the mix of primary energy sources for electricity generation. We find that, relative to continued use of gasoline-powered vehicles, the use of electr...

  12. Soft Skills for Hard Impact

    Science.gov (United States)

    Grigorov, Ivo; Davidson, Joy; Knoth, Petr; Kuchma, Iryna; Schmidt, Birgit; Rettberg, Najla; Rogrigues, Eloy

    2015-04-01

    Marine and Earth Science graduates will be under increasing pressure in future to delve into research questions of relevance to societal challenges. Even fundamental research focused on basic processes of the environment and universe will in the coming decade need to justify their societal impact. As the Research Excellence Frameworks (REF) for research evaluation shift more and more away from the classical Impact Factor and number of peer-reviewed publications to "societal impact", the question remains whether the current graduates, and future researchers, are sufficiently prepared to deal with this reality. The essential compliment of skills beyond research excellence, rigor and method are traditionally described as "soft skills". This includes how to formulate an argument, how to construct a scientific publication, how to communicate such publications to non-experts, place them in context of societal challenges and relevant policies, how to write a competitive proposal and "market" one's research idea to build a research group around an interesting research topic. Such "soft skills" can produce very measurable and concrete impact for career development, but are rarely provided systematically and coherently by graduate schools in general. The presentation will focus on Open Science as a set of "soft skills", and demonstrate why graduate schools should train Open Science competencies alongside research excellence by default. Open Science is about removing all barriers to research process and outputs, both published and unpublished, and directly supports transparency and reproducibility of the research process. Open Science as a set of news competencies can also foster unexpected collaborations, engage citizen scientists into co-creation of solutions to societal challenges, as well as use concepts of Open Science to transfer new knowledge to the knowledge-based private sector, and help them with formulating more competitive research proposals in future.

  13. Impact origin of the Moon

    Energy Technology Data Exchange (ETDEWEB)

    Slattery, W.L.

    1998-12-31

    A few years after the Apollo flights to the Moon, it became clear that all of the existing theories on the origin of the Moon would not satisfy the growing body of constraints which appeared with the data gathered by the Apollo flights. About the same time, researchers began to realize that the inner (terrestrial) planets were not born quietly -- all had evidences of impacts on their surfaces. This fact reinforced the idea that the planets had formed by the accumulation of planetesimals. Since the Earth`s moon is unique among the terrestrial planets, a few researchers realized that perhaps the Moon originated in a singular event; an event that was quite probable, but not so probable that one would expect all the terrestrial planets to have a large moon. And thus was born the idea that a giant impact formed the Moon. Impacts would be common in the early solar system; perhaps a really large impact of two almost fully formed planets of disparate sizes would lead to material orbiting the proto-earth, a proto-moon. This idea remained to be tested. Using a relatively new, but robust, method of doing the hydrodynamics of the collision (Smoothed-Particle Hydrodynamics), the author and his colleagues (W. Benz, Univ. of Arizona, and A.G.W. Cameron, Harvard College Obs.) did a large number of collision simulations on a supercomputer. The author found two major scenarios which would result in the formation of the Moon. The first was direct formation; a moon-sized object is boosted into orbit by gravitational torques. The second is when the orbiting material forms a disk, which, with subsequent evolution can form the Moon. In either case the physical and chemical properties of the newly formed Moon would very neatly satisfy the physical and chemical constraints of the current Moon. Also, in both scenarios the surface of the Earth would be quite hot after the collision. This aspect remains to be explored.

  14. Leadership style : Impact on employee

    OpenAIRE

    Taiwo, Olawale

    2013-01-01

    This thesis studies and discusses the impact leadership management has on employee creativity and output. In order to bring out the best in an employee, the role job satisfaction and performance appraisal play can’t be underestimated in the working environment. The research was approved by the human resources department of Lorna LTD, the case company, to ascertain the level of contentment of its employees. The purpose of this research is to maximize employee output at Lorna LTD and re...

  15. INTERORGANIZATIONAL NETWORKING IMPACT TO INNOVATION

    OpenAIRE

    Evelina Šakalytė; Ilona Bartuševičienė

    2014-01-01

    Purpose – to distinguish main inter-organizational networking characteristics and emphasize impact to innovation within the company and between related actors. Network formation is one of the essential factors to effective business performance and fostering competitiveness. The emergency of growing competition and influence of globalization leads companies to effectively use inner-sources and capabilities in order to be ahead of competitors. Design/methodology/approach – scientific litera...

  16. Impact: What Influences Finance Research?

    OpenAIRE

    Tom Arnold

    2003-01-01

    Which journal articles have had the most impact on finance research? Which journals dominated finance research in the 1990s? We answer these and similar questions using a comprehensive sample of journals, an extensive time period, and a new ranking method that avoids problems inherent in the existing literature. Among our findings: six of the 10 articles most highly cited by finance journals were published in econometrics or economics journals; Journal of Finance has the most citations, but i...

  17. Economic impact of RVF outbreaks

    OpenAIRE

    Antoine-Moussiaux, Nicolas; Chevalier, Véronique; Peyre, Marisa; Abdo-Salem, Shaïf; Bonnet, Pierre; Roger, François

    2012-01-01

    Dwarfing the direct losses due to ruminant abortions and flock mortality, the main economic impact of RVF is systemic and ensues from the trade restrictions aimed at its containment. Indeed, past outbreaks of RVF in East Africa and Middle East came as disturbing events in a commercial context of high specialization in trade of small ruminants and interdependence between East-African exporters and the Middle-Eastern importing countries. The two successive bans imposed by Middle-Eastern countri...

  18. Impacts of European livestock production

    OpenAIRE

    Leip, Adrian; Billen, Gilles; Garnier, Josette; Grizzetti, Bruna; LASSALETTA, LUIS; Reis, Stefan; Simpson, David; Sutton, M. A.; Vries, de, H.J.C.; Weiss, Franz; Westhoek, Henk

    2015-01-01

    Livestock production systems currently occupy around 28% of the land surface of the European Union (equivalent to 65% of the agricultural land). In conjunction with other human activities, livestock production systems affect water, air and soil quality, global climate and biodiversity, altering the biogeochemical cycles of nitrogen, phosphorus and carbon. Here, we quantify the contribution of European livestock production to these major impacts. For each environmental effect, the contribution...

  19. Digital Economy Impact on Society

    OpenAIRE

    Lazãr Cristina; Epure Dãnuþ Tiberius; Spãtariu Elena Cerasela

    2011-01-01

    With this study we’re trying to bolster up the idea that digitization of information combined with the Internet is a form of general purpose technology, which rose a wide range of new possible combinations that could be provided by the digital economy. The impact of the digital economy over societies can be seen and recognized even if only part of it is measurable. The effects of digitalization the economy are seen more in the new activities and products than the productivity.

  20. Hypertension: A Social Impact Disease

    OpenAIRE

    KANTACHUVESSİRİ, AREE

    2013-01-01

    Abstract: Hypertension is one of the leading problemsof the worldwide public health. As the group ofcardiovascular diseases  is the number one killer,hypertension should be controlled even in the level ofindividual or country. From its genesis, social theoriescan explain its increasing prevalence and apply for itsprimary prevention. In fact, hypertension is a social-impact disease, particularly, in the globaliz  world. Thisarticle demonstrates how social changes(Westernization) influence the ...