Vergleich einiger Auswertungsverfahren für dynamische Festigkeitsuntersuchungen mit konstanter und mit steigender Belastung an Stahl in verschiedenen Wärmebehandlungszuständen*) / Comparison of evaluation methods on the basis of Wöhler and Locati results for the estimation of fatigue strength of steel subjected to different heat treatments / Comparaison de quelques meðodes d’evaluation pour des essais de fatigue a charge constante et progressive sur l’acier en differents etats de traitement thermique

1968 ◽  
Vol 10 (11) ◽  
pp. 365-370
Author(s):  
Dieter Dengel
Keyword(s):  
Fatigue Strength ◽  
Evaluation Methods ◽  
Heat Treatments ◽  
Traitement Thermique ◽  
A Charge

scholarly journals The Effect of Heat Treatments on the Fatigue Strength of H13 Hot Work Tool Steel

2018 ◽  
Author(s):  
Ruhi Yeşildal
Keyword(s):  
Fatigue Strength ◽  
Heat Treatments ◽  
Fatigue Tests ◽  
Bending Test ◽  
Test Machine ◽  
Hot Work Steel ◽  
Tempering Treatment ◽  
Rotating Bending ◽  
And Behavior ◽  
Quenching And Tempering

The fatigue strength of the hot work steel depends on various factors, including the mechanical, properties and behavior and bulk and the surface under layer, the microstructural features as well as heat treatments. The influence of a series of heat treatments on the fatigue strength of H13 hot work steel was investigated. Different preheating, quenching and tempering treatments were applied to four sets of specimens and fatigue tests were conducted at room temperature using a rotating bending test machine. All heat treatments resulted in a certain improvement of the fatigue strength. Highest fatigue strength obtained by applying a double tempering heat treatment (first tempering at 550 °C for two hours and second tempering at 610 °C for two hours) after initial preheating and quenching. One tempering treatment (550 °C for two hours after preheating and quenching) did not significantly improve the fatigue strength.

scholarly journals Impacto de la modalidad de carga de fluidos en el diagnóstico de la capacidad de respuesta a volumen

1970 ◽  
Vol 10 (6) ◽  
pp. 6
Author(s):  
Juan Pedro Macias Pingarrón ◽  
Maria Dolores Torrado Criado ◽  
Joaquin Garcia Guerrero ◽  
Fernando Sanchez Espinosa
Keyword(s):  
Evaluation Methods ◽  
Liquid Volume ◽  
Infusion Time ◽  
Liquid Type ◽  
The Difference ◽  
The Moment ◽  
A Charge

El objetivo de este estudio fue describir la “carga de volumen” y evaluar la diferencia en la proporción de "respondedores" (PR) según el tipo de fluido, el volumen, la duración de la infusión y el momento de la evaluación. Métodos: Se realizaron búsquedas en MEDLINE y Embase para estudios que utilizan la carga de volumen como una prueba de precarga cardíaca con una descripción de la técnica, una definición reportada de capacidad de respuesta de fluidos y PR. El resultado primario fue la PR media, según el volumen de líquido, el tipo de líquidos, la tasa de infusión y el tiempo de evaluación. Resultados: se incluyeron un total de 85 estudios (3601 pacientes) en el análisis. Las PR fueron 54.4% (IC 95% 46.9-62.7) donde se administró <500 ml, 57.2% (IC 95% 52.9-61.0) donde se administraron 500 ml y 60.5% (IC 95% 35.9-79.2) donde> 500 ml fue administrado (p = 0.71). El PR no se vio afectado por el tipo de fluido. La RP fue similar entre los pacientes a los que se administró una carga de volumen durante <15 minutos (59.2%, IC 95% 54.2-64.1) y durante 15-30 minutos (57.7%, IC 95% 52.4-62.4, p = 1). Cuando el tiempo de infusión fue ≥30 minutos, hubo una PR menor de 49.9% (IC 95% 45.6-54, p = 0.04). La respuesta se evaluó al final de la exposición a los fluidos, entre 1 y 10 minutos, y > 10 minutos después de la exposición a los fluidos. Las proporciones de respondedores fueron 53.9%, 57.7% y 52.3%, respectivamente (p = 0.47). Conclusiones: el PR disminuye con un tiempo de infusión largo. Es deseable estandarizar la carga de volumen. Abstract The purpose of this study was to describe the ‘charge of volume’ and evaluate the difference in proper proportion for ‘responders’ (PR) according the type of liquid, volume, the timing of infusion and the moment of evaluation. Methods: Medline and Embase searches were made for studies using charge of volumen as a cardiac precharge test among a technique description, fluid  response capacities reported definition and PR. Primary results were average PR, according liquid volumen, liquid type, infusion ratio and time for evaluation. Results: A total of 85 studies (3,601 patients) for the analysis. PR were 54.4% (IC 95% 46.9-62.7) where <500 ml was administrated 57.2% (IC 95% 52.9-61.0) where 500 ml was administrated and 60.5% (IC 95% 35.9-79.2) where >500 ml was administrated (p=0.71). PR was not influenced by the type of fluid. RP was similar among patients given a charge of volumen during <15 minutes  (59.2%, IC 95% 54.2-64.1) and during 15-30 minutes (57.7%, IC 95% 52.4-62.4, p = 1). In time of infusion ≥30 minutes, a lesser 49.9% (IC 95% 45.6-54, p = 0.04) PR happened. Response was evaluated at the end of fluid exposure between 1 and 10 minutes, and <10 minutes after fluid exposure. Responder´s proportion was 53.9%, 57.7% y 52.3% (p=0.47). Findings: PR decreases in a long infusion time.  Standardise charge of volumen is desirable.

scholarly journals The effect of post heat treatments on bending fatigue strength and wear characteristics of TiC coated steels.

1990 ◽  
Vol 2 (1) ◽  
pp. 13-16
Author(s):  
Munetoh Hashimoto ◽  
Masaki Shiratori ◽  
Shin-ici Nagashima ◽  
Syouhei Murayama ◽  
Kazuhiro Saito ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Heat Treatments ◽  
Bending Fatigue ◽  
Wear Characteristics ◽  
Bending Fatigue Strength

Evaluation Methods of Energy-Storable Dye-Sensitized Solar Cells

2010 ◽  
Vol 658 ◽  
pp. 507-510
Author(s):  
Yosuke Saito ◽  
Kentaro Iwata ◽  
Satoshi Uchida ◽  
Takaya Kubo ◽  
Hiroshi Segawa
Keyword(s):  
Output Power ◽  
Dye Sensitized Solar Cells ◽  
Evaluation Methods ◽  
Electrode System ◽  
Solar Irradiation ◽  
Rechargeable Battery ◽  
Low Light ◽  
Dye Sensitized ◽  
A Charge ◽  
Sensitized Solar Cells

Energy-storable dye-sensitized solar cell (ES-DSSC), which possesses a unique three-electrode system composed of a photoanode, a counter electrode and a charge-storage electrode, is a practical solar rechargeable battery. The ES-DSSC is able to yield output power even in the dark after photocharging and suppress the fluctuation of the output power under the capricious solar irradiation. In this study, the evaluation methods of the ES-DSSC performances were investigated toward their practical use under various illumination conditions. The ES-DSSCs were found to be able to work even under low light intensity. Unlike conventional DSSC array, the ES-DSSC array coupled in a series connection gave a stable output voltage when one of the cells or both cells were shadowed.

scholarly journals Low Pressure Carbonitriding of Steel Alloys with Boron and Niobium Additions

2019 ◽  
Author(s):  
Larissa Vilela Costa ◽  
Kip O. Findley ◽  
Vincent Lelong
Keyword(s):  
Heat Treatment ◽  
Fatigue Strength ◽  
Gear Tooth ◽  
Low Pressure ◽  
Heat Treatments ◽  
Steel Alloys ◽  
Bending Fatigue ◽  
Nb Microalloying ◽  
Nb Additions

Abstract Low pressure carbonitriding (LPCN) has the potential to improve impact and fatigue strength, with gears being an example application, through the enrichment of nitrogen in addition to carburizing at higher heat treatment temperatures. In this study, the LPCN response of four different steel alloys is investigated. The influence of unprotected boron is evaluated by comparing the LPCN response of 20MnCr5 with and without boron additions. The influence of Nb microalloying is assessed by comparing the LPCN response of 8620 with and without Nb additions. Low pressure carbonitriding heat treatments were developed to achieve case depths of 0.65 to 0.75 mm in each alloy. The hardness and case microstructure are correlated to bending fatigue response measured with Brugger fatigue specimens, which are designed to simulate the root of a gear tooth.

Influence of Heat Treatments on Microstructures in an Fe-Co-V Alloy

1974 ◽  
Vol 32 ◽  
pp. 512-513
Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Supersaturated Solid Solution ◽  
Cell Formation ◽  
Heat Treatments ◽  
Air Cooling ◽  
Iced Brine ◽  
Transmission Electron ◽  
The Matrix ◽  
Bcc Structure

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.

Microstructural Development in Nb-Ti Multifilamentary Superconductors During Processing

1985 ◽  
Vol 43 ◽  
pp. 190-191
Author(s):  
A. W. West
Keyword(s):  
Heat Treatment ◽  
Critical Current Density ◽  
Copper Matrix ◽  
Wire Drawing ◽  
Heat Treatments ◽  
Microstructural Development ◽  
Final Size ◽  
Density Values ◽  
The Wire ◽  
Multifilamentary Superconductors

The influence of the filament microstructure on the critical current density values, Jc, of Nb-Ti multifilamentary superconducting composites has been well documented. However the development of these microstructures during composite processing is still under investigation.During manufacture, the multifilamentary composite is given several heat treatments interspersed in the wire-drawing schedule. Typically, these heat treatments are for 5 to 80 hours at temperatures between 523 and 573K. A short heat treatment of approximately 3 hours at 573K is usually given to the wire at final size. Originally this heat treatment was given to soften the copper matrix, but recent work has shown that it can markedly change both the Jc value and microstructure of the composite.

Microstructure Development in a High Current Density NbTi Superconducting Composite

1985 ◽  
Vol 43 ◽  
pp. 186-189
Author(s):  
P. J. Lee ◽  
D. C. Larbalestier
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Cold Drawing ◽  
Heat Treatments ◽  
Grain Structure ◽  
Fine Grain ◽  
Boundary Film ◽  
Quantitative Basis ◽  
Cold Worked ◽  
Very High

Several features of the metallurgy of superconducting composites of Nb-Ti in a Cu matrix are of interest. The cold drawing strains are generally of order 8-10, producing a very fine grain structure of diameter 30-50 nm. Heat treatments of as little as 3 hours at 300 C (∼ 0.27 TM) produce a thin (1-3 nm) Ti-rich grain boundary film, the precipitate later growing out at triple points to 50-100 nm dia. Further plastic deformation of these larger a-Ti precipitates by strains of 3-4 produces an elongated ribbon morphology (of order 3 x 50 nm in transverse section) and it is the thickness and separation of these precipitates which are believed to control the superconducting properties. The present paper describes initial attempts to put our understanding of the metallurgy of these heavily cold-worked composites on a quantitative basis. The composite studied was fabricated in our own laboratory, using six intermediate heat treatments. This process enabled very high critical current density (Jc) values to be obtained. Samples were cut from the composite at many processing stages and a report of the structure of a number of these samples is made here.

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