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Resistance of six cast high-temperature alloys to cracking caused by thermal shock

Description: Report presenting an investigation to determine the relative resistance of six cast high-temperature alloys to cracking caused by thermal shock. The alloys tested included S-816, S-590, Vitallium, 422-19, X-40, and Stellite 6. Results regarding the tabulation of cycles to failure, crack properties, metallographic examination, and some curves of deformation data are provided.
Date: February 1950
Creator: Whitman, M. J.; Hall, R. W. & Yaker, C.
Partner: UNT Libraries Government Documents Department

Thermal-shock resistance of a ceramic comprising 60 percent boron carbide and 40 percent titanium diboride

Description: Thermal-shock resistance of a ceramic comprising 60 percent boron carbide and 40 percent titanium diboride was investigated. The material has thermal shock resistance comparable to that of NBS body 4811C and that of zirconia, but is inferior to beryllia, alumina, and titanium-carbide ceramals. It is not considered suitable for turbine blades.
Date: March 16, 1953
Creator: Yeomans, C. M. & Hoffman, C. A.
Partner: UNT Libraries Government Documents Department

Experimental Studies on Attenuation of Pressure Waves Induced by Thermal Shocks

Description: High magnitude pressure waves are expected in the mercury-filled Spallation Neutron Source target system. An appropriate measure is needed to protect the target system from such high pressure waves. It has been known that inclusion of devices like scattering centers in the pressure field will attenuate pressure waves by scattering waves between scattering centers. A series of experiments have been conducted to test such a concept. After verifying the concept by performing simple scoping experiments, fives series of experiments were conducted with various configuration to measure changes in sound speed and pressure amplitude with inclusion of various scattering centers. Results indicate that for the conditions of our test, no significant change in sound speed was observed; however, substantial attenuation of pressure waves was detected with scattering centers in mercury.
Date: February 13, 2001
Creator: Kim, S.H.
Partner: UNT Libraries Government Documents Department

Overcoming Thermal Shock Problems in Liquid Targets

Description: Short pulse accelerator-driven neutron sources such as the Spallation Neutron Source (SNS) employ high-energy proton beam energy deposition in heavy metal (such as mercury) over microsecond time frames. The interaction of the energetic proton beam with the mercury target leads to very high heating rates in the target. Although the resulting temperature rise is relatively small (a few {degree}C ), the rate of temperature rise is enormous ({approximately}10{sup 7} C/s) during the very brief beam pulse ({approximately}0.58 {micro}s). The resulting thermal-shock induced compression of the mercury leads to the production of large amplitude pressure waves in the mercury that interact with the walls of the mercury target and the bulk flow field. Safety-related operational concerns exist in two main areas, viz., (1) possible target enclosure failure from impact of thermal shocks on the wall due to its direct heating from the proton beam and the loads transferred from the mercury compression waves, and (2) impact of the compression-cum-rarefaction wave-induced effects such as cavitation bubble emanation and fluid surging. Preliminary stress evaluations indicate stress levels approaching yielding conditions and beyond in select regions of the target. Also, the induction of cavitation (which could assist in attenuation) can also release gases that may accumulate at undesirable locations and impair heat transfer.
Date: June 2000
Creator: Taleyarkhan, R. P. & Kim, S. H.
Partner: UNT Libraries Government Documents Department

Thermal shock resistance and high-temperature strength of a molybdenum disilicide - aluminum oxide ceramic

Description: From Summary: "A ceramic consisting nominally of 75 percent molybdenum disilicide and 25 percent alumium oxide was investigated to determine its thermal shock characteristics and high-temperature strength properties. In a rim-quench thermal shock evaluation, the material was found to be superior to pure molybdenum disilicide. In a simulated altitude blow-out test, the material withstood an average of 2.5 cycles when quenched from 1800 degrees Fahrenheit."
Date: October 1, 1953
Creator: Maxwell, W. A. & Smith, R. W.
Partner: UNT Libraries Government Documents Department

Criteria for Determining Element Size and Time Step for Thermal Shock Simulation

Description: Rapid energy deposition into spallation source targets can lead to their temperature rise at enormous rates, giving rise to dynamic thermoelastic stresses. Understanding and predicting the resulting stress waves are crucial for robust design and safe operation of such devices. To simulate the thermal shock phenomenon accurately, many factors should be carefully considered, such as geometry, surface condition, energy deposition profile, equation of state, possible cavitation, viscous damping, rate-dependent constitutive equation, element size, and time step. In this paper a closed form expression for the induced stress in slender bars with distributed energy deposition has been directly derived; it is then used to test the accuracy of computed results with FEA codes. It was found that significant errors can occur unless care is taken to restrict element size and time step depending on the boundary conditions, steepness of temperature profiles and rise rate. Criteria have been proposed for determining the above two parameters. Numerical simulation with the well-established ANSYS5.5 code system showed that excellent results could be achieved if the proposed criteria are met.
Date: February 13, 2001
Creator: Zheng, J.
Partner: UNT Libraries Government Documents Department

Turbojet engine investigation of effect of thermal shock induced by external water-spray cooling on turbine blades of five high-temperature alloys

Description: Report presenting an investigation of the thermal-shock effect of water-spray impingement upon turbine rotor blades subjected to rated engine operating conditions using external water-spray cooling. Turbine-blade cooling water was turned on and off in cycles which employed either sudden or gradual injection of cooling water. Results regarding blades modified and unmodified for rotating injection are provided.
Date: December 19, 1955
Creator: Freche, John C. & Hickel, Robert O.
Partner: UNT Libraries Government Documents Department

Technical Letter Report Development of Flaw Size Distribution Tables Including Effects of Flaw Depth Sizing Errors for Draft 10CFR 50.61a (Alternate PTS Rule) JCN-N6398, Task 4

Description: This document describes a new method to determine whether the flaws in a particular reactor pressure vessel are consistent with the assumptions regarding the number and sizes of flaws used in the analyses that formed the technical justification basis for the new voluntary alternative Pressurized Thermal Shock (PTS) rule (Draft 10 CFR 50.61a). The new methodology addresses concerns regarding prior methodology because ASME Code Section XI examinations do not detect all fabrication flaws, they have higher detection performance for some flaw types, and there are flaw sizing errors always present (e.g., significant oversizing of small flaws and systematic under sizing of larger flaws). The new methodology allows direct comparison of ASME Code Section XI examination results with values in the PTS draft rule Tables 2 and 3 in order to determine if the number and sizes of flaws detected by an ASME Code Section XI examination are consistent with those assumed in the probabilistic fracture mechanics calculations performed in support of the development of 10 CFR 50.61a.
Date: April 22, 2013
Creator: Simonen, Fredric A.; Gosselin, Stephen R. & Doctor, Steven R.
Partner: UNT Libraries Government Documents Department

Comparison of glass surfaces as a countertop material to existing surfaces

Description: Gleen Glass, a small production glass company that creates countertops, was selected for the Technology Assistance Program through Pacific Northwest National Laboratory. Gleen Glass was seeking material property analysis comparing glass as a countertop material to current surfaces (i.e. marble, granite and engineered stone). With samples provided from Gleen Glass, testing was done on granite, marble, and 3 different glass surfaces ('Journey,' 'Pebble,' and 'Gleen'). Results showed the glass surfaces have a lower density, lower water absorption, and are stronger in compressive and flexural tests as compared to granite and marble. Thermal shock tests showed the glass failed when objects with a high thermal mass are placed directly on them, whereas marble and granite did not fracture under these conditions.
Date: September 1, 2011
Creator: Turo, Laura A. & Winschell, Abigail E.
Partner: UNT Libraries Government Documents Department

Thermal shock behavior of alumina/MoSi2 plasma sprayed laminated composites

Description: Alumina (Al{sub 2}O{sub 3}) is very susceptible to thermal shock, which leads to strength degradation. By reinforcing Al{sub 2}O{sub 3} with molybdenum disilicide (MoSi{sub 2}) layers, the tolerance to damage caused by thermal shock can be improved. The thermal shock resistance of plasma sprayed Al{sub 2}O{sub 3}/MoSi{sub 2} laminated composites were investigated. Three laminate microstructures having different layer thickness were fabricated by atmospheric plasma spraying while maintaining a 50/50-volume fraction. Quenching experiments done on 4-point bend bars showed a gradual decrease in the strength as the change in temperature ({Delta}T) increased. Thermal shock resistant parameters (R{prime} and R-quadruple prime) provided a representative numerical value of the thermal shock resistance for the laminated composites. The corresponding material properties for the different microstructures were determined experimentally in order to calculate the R{prime} and R quadruple prime values. The intermediate layered composite showed the highest R-quadruple prime va1ue at 1061 {micro}m, while the thin layered composite had the highest R{prime} value at 474 W/m.
Date: January 1, 2001
Creator: Castro, R. G. (Richard G.); Petrovic, J. J.; Vaidya, R. U. (Rajendra U.) & Mendoza, D. (Daniel)
Partner: UNT Libraries Government Documents Department

Development of Submerged Entry Nozzles that Resist Clogging

Description: Accretion formation and the associated clogging of SENs is a major problem for the steel industry leading to decreased strand speed, premature changing of SENs or strand termination and the associated reductions in productivity, consistency, and steel quality. A program to evaluate potentially clog resistance materials was initiated at the University of Missouri-Rolla. The main objective of the research effort was to identify combinations of steelmaking and refractory practices that would yield improved accretion resistance for tundish nozzles and submerged entry nozzles. A number of tasks were identified during the initial kick-off meeting and each was completed with two exceptions, the thermal shock validation and the industrial trials. Not completing these two tasks related to not having access to industrial scale production facilities. Though much of the results and information generated in the project is of proprietary nature.
Date: October 14, 2002
Creator: Smith, Dr. Jeffrey D. & Peasle, Kent D.
Partner: UNT Libraries Government Documents Department

Thermal-Shock Assessments for National Spallation Neutron Source Target System

Description: A perspective overview is provided on preliminary observations from simulations of thermal shock in the National Spallation Neutron Source (NSNS) at various power levels. Significant damage potential to structures may be present only at high ({approx}5-MW) power levels which may require inclusion of mitigative features. The simulation framework being utilized and under development is presented. Focused experiments are being conducted to derive key benchmarking data for the simulation framework as also for timely resolution of key design and operational-safety issues.
Date: August 1, 2001
Creator: Taleyarkhan, R
Partner: UNT Libraries Government Documents Department

Results of the Thermal-Shock Modeling and Analyses for the National Spallation Neutron Source

Description: An overview is provided on preliminary observations from simulations of thermal shock in the National Spallation Neutron Source (NSNS) at various power levels. The simulation framework being utilized and under development is presented. Results of simulations for pressure and stress profiles at key locations are presented. Variation of results with possible onset of mercury cavitation were modeled and the results are discussed. Significant reductions in stresses on structures may be possible with cavitation onset. Key thermal-shock related issues are highlighted.
Date: August 1, 2001
Creator: Taleyarkan, . .
Partner: UNT Libraries Government Documents Department

Slang characterization and removal using pulse detonation technology during coal gasification

Description: Boiler slagging and fouling as a result of inorganic impurities in combustion gases being deposited on heat transfer tubes have caused severe problems in coal-fired power plant operation. These problems are fuel, system design, and operating condition dependent. Pulse detonation technology for the purpose of removing slag and fouling deposits in coal-fired utility power plant boilers offers great potential. The detonation wave technique based on high impact velocity with sufficient energy and thermal shock on the slag deposited on gas contact surfaces offers a convenient, inexpensive, yet efficient and effective way to supplement existing slag removal methods. These detonation waves have been demonstrated experimentally to have exceptionally high shearing capability important to the task of removing slag and fouling deposits. The experimental results show that the single shot detonation wave is capable of removing the entire slag (types of slag deposited on economizer) even at a distance of 8 in. from the exit of a detonation engine tube. Wave strength and slag orientation also have different effects on the chipping off of the slag. This paper discusses about the results obtained in effectively removing the economizer slag.
Date: March 25, 1997
Creator: Huque, Z.; Mei, D.; Biney, P.O. & Zhou, J.
Partner: UNT Libraries Government Documents Department

A Review of Large-Scale Fracture Experiments Relevant to Pressure Vessel Integrity Under Pressurized Thermal Shock Conditions

Description: Numerous large-scale fracture experiments have been performed over the past thirty years to advance fracture mechanics methodologies applicable to thick-wall pressure vessels. This report first identifies major factors important to nuclear reactor pressure vessel (RPV) integrity under pressurized thermal shock (PTS) conditions. It then covers 20 key experiments that have contributed to identifying fracture behavior of RPVs and to validating applicable assessment methodologies. The experiments are categorized according to four types of specimens: (1) cylindrical specimens, (2) pressurized vessels, (3) large plate specimens, and (4) thick beam specimens. These experiments were performed in laboratories in six different countries. This report serves as a summary of those experiments, and provides a guide to references for detailed information.
Date: January 29, 2001
Creator: Pugh, C. E.
Partner: UNT Libraries Government Documents Department

Dynamic Strain on Thin Diaphragms of a Mercury Target During 800-MeV Proton Thermal Shock Tests

Description: Extrinsic Fabry-Perot Interferometric fiber optic sensors were used to measure dynamic strains on thin diaphragms of a liquid mercury target, which was subjected to intense 800-MeV proton thermal shock tests. The mercury target is engineered with very thin end plates or diaphragms (either 0.6 mm or 1.9 mm) for studying large strain effects. During thermal shock tests, the mercury in the target interacted with an intense pulsed beam of 2.4x10{sup 13 protons}. The resulting pressure waves lead to large strains exceeding 250 microstrains on a 0.6-mm diaphragm. Significant factors relative to the accuracy of strain measurements are emphasized, such as the sensor air gap, alignment of sensors, and frequency response of the strain instrument. In this paper, dynamic strains measured on thin diaphragms are described and discussed.
Date: November 13, 1999
Creator: Allison, S.W.; Andriulli, J.B.; Cates, M.R.; Earl, D.D.; Haines, J.R.; Morrissey, F.X. et al.
Partner: UNT Libraries Government Documents Department

Fracture behavior of advanced ceramic hot-gas filters

Description: Microstructural, mechanical, and thermal-shock behavior of hot-gas candle filters obtained from different manufacturers have been evaluated. These filters include both monolithic ceramic and composite materials. Based on the results obtained so far, composite filters perform better than monolithic ceramic filters in a thermal-shock environment. During thermal-shock testing, the monolithic ceramic filters failed in a brittle (catastrophic) mode while composite filters showed a noncatastrophic mode of failure and very little degradation in ultimate strength. Fractographic evaluations were performed to identify and characterize critical flaws in Nextel fibers for the determination of in-situ fiber strength in Nextel/SiC filters. Average in--situ fiber strength was determined to be 1.7 GPa.
Date: May 1995
Creator: Singh, J. P.; Singh, D.; Smith, J. & Volz, H.
Partner: UNT Libraries Government Documents Department

Modeling and Analysis of AGS (1998) Thermal Shock Experiments

Description: An overview is provided on modeling and analysis of thermal shock experiments conducted during 1998 with high-energy, short-pulse energy deposition in a mercury filled container in the Alternating Gradient Synchrotron (AGS) facility at Brookhaven National Laboratory (BNL). The simulation framework utilized along with the results of simulations for pressure and strain profiles are presented. While the magnitude of penk strain predictions versus data are in reasonable agreement, the temporal variations were found to differ significantly in selected cases, indicating lack of modeling of certain physical phenomena or due to uncertainties in the experimental data gathering techniques. Key thermal-shock related issues and uncertainties are highlighted. Specific experiments conducted at BNL's AGS facility during 1998 (the subject of this paper) involved high-energy (24 GeV) proton energy deposition in the mercury target over a time frame of - 0.1s. The target consisted of an - 1 m. long cylindrical stainless steel shell with a hemispherical dome at the leading edge. It was filled with mercury at room temperature and pressure. Several optical strain gages were attached to the surface of the steel target. Figure 1 shows a schematic representation of the test vessel along with the main dimensions and positions of three optical strain gages at which meaningful data were obtained. As
Date: November 14, 1999
Creator: Haines, J.R.; Kim, S.H. & Taleyarkhan, R.P.
Partner: UNT Libraries Government Documents Department

Plasma Sprayed Pour Tubes and Other Melt Handling Components for Use in Gas Atomization

Description: Ames Laboratory has successfully used plasma sprayed ceramic components made from yttria stabilized zirconia as melt pouring tubes for gas atomization for many years. These tubes have proven to be strong, thermal shock resistant and versatile. Various configurations are possible both internally and externally. Accurate dimensions are achieved internally with a machined fugitive graphite mandrel and externally by diamond grinding. The previous study of the effect of spray parameters on density was extended to determine the effect of the resulting density on the thermal shock characteristics on down-quenching and up-quenching. Encouraging results also prompted investigation of the use of plasma spraying as a method to construct a melt pour exit stopper that is mechanically robust, thermal shock resistant, and not susceptible to attack by reactive melt additions. The Ames Laboratory operates two close-coupled high pressure gas atomizers. These two atomizers are designed to produce fine and coarse spherical metal powders (5{mu} to 500{mu} diameter) of many different metals and alloys. The systems vary in size, but generally the smaller atomizer can produce up to 5 kg of powder whereas the larger can produce up to 25 kg depending on the charge form and density. In order to make powders of such varying compositions, it is necessary to have melt systems capable of heating and containing the liquid charge to the desired superheat temperature prior to pouring through the atomization nozzle. For some metals and alloys this is not a problem; however for some more reactive and/or high melting materials this can pose unique challenges. Figure 1 is a schematic that illustrates the atomization system and its components.
Date: April 1, 2011
Creator: Byrd, David; Rieken, Joel; Heidloff, Andy; Besser, Matthew & Anderson, Iver
Partner: UNT Libraries Government Documents Department

AISI/DOE Advanced Process Control Program Vol. 3 of 6: Improved Liquid Steel Feeding for Slab Casters

Description: This report describes the development, construction and testing of the Electromagnetic Valve System (EVS), conducted as a project entitled ''Improved Liquid Steel Feeding System for Slab Casters''. This program ran from November 1992 to January 1995. Many of the technical issues in bringing the EVS to the steel industry were identified and resolved during the course of the program. During this time, significant hardware improvements in Westinghouse's electromagnetic valve were made to easily integrate it with existing continuous casting processes,. An improved refractory nozzle was developed and tested which had superior thermal shock and anti-cracking performance. In addition, several trials were conducted with molten steel to verify the proof-of-principle of the electromagnetic valve and its auxiliary equipment. However, improvements in other conventional pouring technologies have greatly diminished the potential value of this project to the steel industry. A such, the program w as canceled by the American Iron and Steel Institute after the conclusion of Phase I
Date: June 30, 1999
Creator: Isaacson, Brent; Slepian, Mike & Richter, Thomas
Partner: UNT Libraries Government Documents Department

Hydrodynamic phenomena of gas-filled chamber due to target implosion in fusion reactors.

Description: Use of an intermediate gas in the reaction chamber of an inertial fusion power reactor is under consideration to decrease the thermal shock to the walls resulting from target implosions. A model was developed and implemented in HEIGHTS package to simulate hydrodynamic and radiation shock waves in the chamber and used to determine the effect of xenon gas at various densities ranging from mtorr up to tens of torr. Numerical calculations for the dense-gas case indicated that two pressure peaks result from the shock wave interacting with the chamber wall, and radiation energy accumulates directly in front of the hydrodynamic shock wave. The shock wave should reach a maximum pressure peak when the chamber gas has a density between the two extremes analyzed. In general, calculated results with our model compared favorably with previously published data.
Date: July 2, 2003
Creator: Sizyuk, V. & Hassanein, A.
Partner: UNT Libraries Government Documents Department

Environmental evaluation of Surface Mounted Devices (SMD)

Description: We evaluated the comparative reliability of solder interconnections used for Leadless Chip Carriers (LCCs), Meaded, and flat-pack hybrid microcircuits mounted on FR-4 glass epoxy printed wiring boards (PWBs). The board assemblies, with solder attached microcircuits, were repeatedly thermal cycled from - 65 to +125{degrees}C. We recognize that this temperature range far exceeds most testing of assemblies. The purposes of these tests were to evaluate worst-case conditions and to obtain comparative information. Identical PWB assemblies, using these three component types, were subjected to both thermal shock testing (1 cycle every 42 minutes) and temperature cycle testing (1 cycle every 3 hours). The double testing evaluated the differences in stress application and evaluated the potential of replacing slow transition, expensive temperature cycle testing (which has been an industry standard for years) with the much more rapid thermal shock testing.
Date: June 1, 1997
Creator: Barr, V.C. & Andrade, A.D.
Partner: UNT Libraries Government Documents Department

CSNI Project for Fracture Analyses of Large-Scale International Reference Experiments (FALSIRE II)

Description: A summary of Phase II of the Project for FALSIRE is presented. FALSIRE was created by the Fracture Assessment Group (FAG) of the OECD/NEA`s Committee on the Safety of Nuclear Installations (CNSI) Principal Working Group No. 3. FALSIRE I in 1988 assessed fracture methods through interpretive analyses of 6 large-scale fracture experiments in reactor pressure vessel (RPV) steels under pressurized- thermal-shock (PTS) loading. In FALSIRE II, experiments examined cleavage fracture in RPV steels for a wide range of materials, crack geometries, and constraint and loading conditions. The cracks were relatively shallow, in the transition temperature region. Included were cracks showing either unstable extension or two stages of extensions under transient thermal and mechanical loads. Crack initiation was also investigated in connection with clad surfaces and with biaxial load. Within FALSIRE II, comparative assessments were performed for 7 reference fracture experiments based on 45 analyses received from 22 organizations representing 12 countries. Temperature distributions in thermal shock loaded samples were approximated with high accuracy and small scatter bands. Structural response was predicted reasonably well; discrepancies could usually be traced to the assumed material models and approximated material properties. Almost all participants elected to use the finite element method.
Date: November 1, 1996
Creator: Bass, B. R.; Pugh, C. E.; Keeney, J.; Schulz, H. & Sievers, J.
Partner: UNT Libraries Government Documents Department