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A Fundamental Investigation of Fretting Corrosion

Description: Note presenting a summary of all phases of an investigation of fretting corrosion that has been conducted over a period of several years. Part I describes a test machine for measuring fretting damage under controlled experimental conditions. Part II presents data for mild steel fretted against itself, with a number of characteristics taken into consideration. Part III suggest a mechanism for the fretting process.
Date: December 1953
Creator: Uhlig, H. H.; Feng, I. Ming; Tierney, W. D. & McClellan, A.
Partner: UNT Libraries Government Documents Department

Coefficient of friction and damage to contact area during the early stages of fretting 2: steel, iron, iron oxide, and glass combinations

Description: Report presenting experiments to study the start of fretting and cause of damage during the early stages of fretting of steel-steel combinations at a frequency 5 cycles per minute, an amplitude of 0.006 inch, a load of 150 grams, in air with relative humidity of less than 10 percent. Pure iron, glass, and iron oxide powder compacts were used in supplementary experiments.
Date: April 1954
Creator: Bailey, John M. & Godfrey, Douglas
Partner: UNT Libraries Government Documents Department

Coefficient of friction and damage to contact area during the early stages of fretting 1: Glass, copper, or steel against copper

Description: Report presenting experiments to measure the coefficient of friction and to determine the damage to the contact area during early stages of fretting of copper at a frequency of 5 cycles per minute. Specimen combinations of copper against glass, copper against copper, and copper against steel, as well as various copper oxide films and powder compacts were used.
Date: September 1953
Creator: Godfrey, Douglas & Bailey, John M.
Partner: UNT Libraries Government Documents Department

Investigation of Fretting Corrosion by Microscopic Observation

Description: Note presenting an investigation using microscopic observation of the action to determine the cause of fretting corrosion. Glass and other noncorrosive materials, as well as metals, were used as specimens. Results regarding metal against metal, metal against nonmetal, and nonmetals against nonmetals are provided.
Date: February 1950
Creator: Godfrey, Douglas
Partner: UNT Libraries Government Documents Department

An Investigation of Fretting Corrosion Under Several Conditions of Oxidation

Description: Note presenting a study to gain information as to the fundamental mechanism of fretting corrosion. The specific questions to be answered were whether chemical action played an important role in fretting of metal surfaces and whether any such action would improve the corrosion resistance of the metal investigated. The results indicated that the chemical action is of primary importance in fretting-corrosion effects and oxide formation does not give any protection to the metals but rather increases the rate of wear.
Date: June 1948
Creator: Sakmann, B. W. & Rightmire, B. G.
Partner: UNT Libraries Government Documents Department

Investigation of Fretting by Microscopic Observation

Description: "An experimental investigation, using microscopic observation and color motion photomicrographs of the action, was conducted to determine the cause of fretting. Glass and other noncorrosive materials, as well as metals, were used as specimens. A very simple apparatus vibrated convex surfaces in contact with stationary flat surfaces at frequencies of 120 cycles or less than l cycle per second, an amplitude of 0.0001 inch, and load of 0.2 pound" (p. 135).
Date: August 31, 1949
Creator: Godfrey, Douglas
Partner: UNT Libraries Government Documents Department

Effectiveness of molybdenum disulfide as a fretting-corrosion inhibitor

Description: Report presenting an investigation of the effectiveness of molybdenum disulfide as a fretting-corrosion inhibitor. Six methods of applying MoS2 to steel specimens was evaluated by noting the number of cycles of vibration required to produce the first evidence of fretting corrosion and by observing the nature of its occurrence. Experiments were conducted with steel balls vibrating in contact with glass flats whereby the action could be microscopically observed.
Date: September 1950
Creator: Godfrey, Douglas & Bisson, Edmond E.
Partner: UNT Libraries Government Documents Department

Considerations for sensitivity analysis, uncertainty quantification, and data assimilation for grid-to-rod fretting

Description: Grid-to-rod fretting is the leading cause of fuel failures in pressurized water reactors, and is one of the challenge problems being addressed by the Consortium for Advanced Simulation of Light Water Reactors to guide its efforts to develop a virtual reactor environment. Prior and current efforts in modeling and simulation of grid-to-rod fretting are discussed. Sources of uncertainty in grid-to-rod fretting are also described.
Date: October 1, 2012
Creator: Pernice, Michael
Partner: UNT Libraries Government Documents Department

Experimental Study on Impact/Fretting Wear in Heat Exchanger Tubes

Description: A data bank of field experiences with heat exchanger tube vibration reveals numerous cases of tube failures at, or near, the baffle. The objective of this study is to provide qualitative impact/fretting wear information for heat exchanger tubes through the performance of a series of tests involving the pertinent parameters: impact force level, between the tube and its support; tube to support plate hole clearance; tube support plate thickness; and tube vibration frequency. The characteristics of impact/fretting wear relative to tube motion pattern, material combination and surrounding fluid were also investigated. The test apparatus consists of a cantilevered tube with a simulated tube support plate at the ''free end''. Tube vibration is induced by an electromagnetic exciter to simulate the flow-induced tube motion occurring in a real heat exchanger at the tube/tube support plate interface. Tests are conducted in air, water, and oil, all at room temperature. Wear rate increases significantly with the magnitude of the impact force between the tube and its support plate; the degree and trend of the wear rates are highly dependent on the mechanical and metallurgical properties of the tube/support material combination; the rate of impact/fretting wear decreases with increasing frequency. An empirical formula is proposed to correlate the experimental impact/fretting wear results.
Date: April 1985
Creator: Cha, J. H.; Wambsganss, M. W. & Jendrzejczyk, J. A.
Partner: UNT Libraries Government Documents Department

MIL-L-87177 and CLT:X-10 Lubricants Improve Electrical Connector Fretting Corrosion Behavior

Description: We have conducted a fretting research project using MIL-L-87177 and CLT: X-10 lubricants on Nano-miniature connectors. When they were fretted without lubricant, individual connectors first exceeded our 0.5 ohm failure criteria from 2,341 to 45,238 fretting cycles. With additional fretting, their contact resistance increased to more than 100,000 ohms. Unmodified MIL-L-87177 lubricant delayed the onset of first failure to between 430,000 and over 20,000,000 fretting cycles. MIL-L-87177 modified by addition of Teflon powder delayed first failure to beyond 5 million fretting cycles. Best results were obtained when Teflon was used and also when both the straight and modified lubricants were poured into and then out of the connector. CLT: X-10 lubricant delayed the onset of first failure to beyond 55 million cycles in one test where a failure was actually observed and to beyond 20 million cycles in another that was terminated without failure. CLT: X-10 recovered an unlubricated connector driven deeply into failure, with six failed pins recovering immediately and four more recovering during an additional 420 thousand fretting cycles. MIL-L-87177 was not able to recover a connector under similar conditions.
Date: October 12, 1999
Partner: UNT Libraries Government Documents Department

MIL-L-87177 Lubricant Bulletproofs Connectors Against Chemical and Fretting Corrosion

Description: Electrical connectors corrode. Even our best SA and MC connectors finished with 50 to 100 microinches of gold over 50 to 100 microinches of nickel corrode. This work started because some, but not all, lots of connectors held in KC stores for a decade had been destroyed by pore corrosion (chemical corrosion). We have identified a MIL-L-87177 lubricant that absolutely stops chemical corrosion on SA connectors, even in the most severe environments. For commercial connectors which typically have thinner plating thicknesses, not only does the lubricant significantly retard effects of chemical corrosion, but also it greatly prolongs the fretting life. This report highlights the initial development history and use of the lubricant at Bell Labs and AT&T, and the Battelle studies and the USAF experience that lead to its deployment to stop dangerous connector corrosion on the F-16. We report the Sandia, HFM&T and Battelle development work, connector qualification, and material compatibility studies that demonstrate its usefulness and safety on JTA and WR systems. We will be applying MIL-L-87177 Connector Lubricant to all new connectors that go into KC stores. We recommend that it be applied to connectors on newly built cables and equipment as well as material that recycles through manufacturing locations from the field.
Date: May 1, 2002
Partner: UNT Libraries Government Documents Department

Tribological Improvements of Carbon-Carbon Composites by Infiltration of Atomic Layer Deposited Lubricious Nanostructured Ceramic Oxides

Description: A number of investigators have reported enhancement in oxidation and wear resistant of carbon-carbon composites (CCC) in the presence of protective coating layers. However, application of a surface and subsurface coating system that can preserve its oxidation and wear resistance along with maintaining lubricity at high temperature remains unsolved. To this end, thermodynamically stable protective oxides (ZnO/Al2O3/ZrO2) have been deposited by atomic layer deposition (ALD) to infiltrate porous CCC and graphite foams in order to improve the thermal stability and wear resistance in low and high speed sliding contacts. Characterization of microstructural evolution was achieved by using energy dispersive x-ray spectroscopy (EDS) mapping in scanning electron microscope (SEM) coupled with focused ion beam (FIB), x-ray tomography, high resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM) and X-ray diffraction (XRD). Evaluation of the tribological properties of CCC coated with abovementioned ALD thin films were performed by employing low speed pure sliding tribometer and a high speed/frequency reciprocating rig to simulate the fretting wear behavior at ambient temperature and elevated temperatures of 400°C.It was determined with x-ray tomography imaging and EDS mapping that ALD ZnO/Al2O3/ZrO2 nanolaminates and baseline ZrO2 coatings exhibited excellent conformality and pore-filling capabilities down to ~100 μm and 1.5 mm in the porous CCC and graphite foam, respectively, which were dependent on the exposure time of the ALD precursors. XRD and HRTEM determined the crystalline phases of {0002} textured ZnO (wurtzite), amorphous Al2O3, and {101}-tetragonal ZrO2. Significant improvements up to ~65% in the sliding and fretting wear factors were determined for the nanolaminates in comparison to the uncoated CCC. A tribochemical sliding-induced mechanically mixed layer (MML) was found to be responsible for these improvements. HRTEM confirmed the presence of a high density of ZnO shear-induced basal stacking faults inside the wear tracks responsible for intrafilm shear velocity ...
Date: August 2011
Creator: Mohseni, Hamidreza
Partner: UNT Libraries

Analysis/control of in-bed tube erosion phenomena in the Fluidized Bed Combustion (FBC) System. Technical progress report No. 5

Description: This technical report summarizes the research work performed and progress achieved during the period of October 1, 1993 to December 31, 1993. Measurement of particle-tube collision frequency was conducted by an electrostatic impact probe in the bench-scale FBC model. Two series of tests were conducted, in one test the probe traversed vertically along the bed axis. The other test conducted that the probe traversed from the center position to the quarter point of bed diagonal and the wall region. The specific weight loss at different tube circumferential was examined to understand the effect of superficial fluidizing velocity. The bottom section of the test tube was found to be more serious erosion than that of the top section. In order to study the effect of tube orientations on in-bed tube erosion, the sample tubes along with four different angles were used. The sample tubes were also placed horizontally and vertically at the center, and vertically near the wall to quantify the effect of the tube location.
Date: January 1, 1994
Creator: Lee, S. W.
Partner: UNT Libraries Government Documents Department

Dynamic tube/support interaction in heat exchanger tubes

Description: The supports for heat exchanger tubes are usually plates with drilled holes; other types of supports also have been used. To facilitate manufacture and to allow for thermal expansion of the tubes, small clearances are used between tubes and tube supports. The dynamics of tube/support interaction in heat exchangers is fairly complicated. Understanding tube dynamics and its effects is important for heat exchangers. This paper summarizes the current state of the art on this subject and to identify future research needs. Specifically, the following topics are discussed: dynamics of loosely supported tubes, tube/support gap dynamics, tube response in flow, tube damage and wear, design considerations, and future research needs. 55 refs., 1 fig.
Date: January 1, 1991
Creator: Chen, S.S.
Partner: UNT Libraries Government Documents Department

Qualification of aluminum for OTEC heat exchangers

Description: The basis for qualification of aluminum as a material for use as tubing in Ocean Thermal Energy Conversion heat exchangers is reviewed. Reference is made to compendia of data from tests of aluminum alloys in natural sea water and to applicable service records. Data from these sources were found to be inadequate to either qualify or disqualify aluminum. They serve only to identify the 5052 alloy and Alclad 3003 or 3004 as being worthy of additional testing under conditions more directly related to what will be encountered in OTEC heat exchangers. The principal deficiency of data from long-time tests in natural sea water is that in almost all of these tests the specimens were exposed under static conditions that caused the surfaces to be covered by marine fouling organisms that would not be present in heat exchanger tubes. The tests did not take into account possible effects of periodic mechanical or chemical treatments to remove fouling or chemical treatments (chlorination) to prevent fouling. A current testing program sponsored by the Department of Energy through Argonne National Laboratory is designed to provide the needed data. Limited tests in high velocity sea water have indicated that aluminum tubes would tolerate the velocities under 10 ft (3 m) per second likely to be used in OTEC heat exchangers.
Date: May 1, 1979
Creator: LaQue, F.L.
Partner: UNT Libraries Government Documents Department