Effects of Specimen Geometry on Characteristic Temperature during Quenching of Heated Metals in Subcooled Water

Narazaki, Michiharu; Fuchizawa, Sadakatsu; Usuba, Masaaki

doi:10.2355/tetsutohagane1955.75.4_634

Cited by 10 publications

(6 citation statements)

References 4 publications

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“…The above-mentioned trends of the MHF-point temperature to become warmer are very different from the experimental results reported by others [5][6][7] for systems, in which the weak-spot effect had been eliminated. Searching for an answer for this phenomenon Fig.…”

Section: Subcooled Boilingcontrasting

confidence: 76%

“…The two types of collapse mechanisms mentioned above have also been reported by Kikuchi et al [7] (using a spherical surface) and Narazaki et al [5] (using a vertical cylindrical surface). Although they have done a qualitative assessment of the phenomenon, so far a quantitative assessment has not been performed.…”

Section: Introductionmentioning

confidence: 68%

“…Contrarily, it is also reported by Narasaki et al [5] that a careful preparation of the boiling surface will result in DT MHF ¼ 200°C even at DT sub ¼ 80 K; this makes it clear that MHF-point temperature can vary drastically depending on the researcher and the apparatus being used. In addition, the above equation predicts values that exceed the thermodynamic limit of liquid superheat (T tls ) for subcoolings larger than DT sub ¼ 14 K; for water at one atmosphere, T tls ¼ 310°C roughly.…”

Section: Introductionmentioning

confidence: 74%

“…This localized low-temperature section corresponds to the support structures of heat transfer surfaces, in relating the present work to published works [5][6][7]. In industrial applications, we can expect the localized low-temperature regions to exist in various forms such as supports, protruded sections, and pointed segments.…”

Section: Analytical Modelmentioning

confidence: 82%

See 3 more Smart Citations

Study on propagative collapse of a vapor film in film boiling (mechanism of vapor-film collapse at wall temperature above the thermodynamic limit of liquid superheat)

Ohtake

Koizumi

2004

International Journal of Heat and Mass Transfer

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Section: Subcooled Boilingcontrasting

confidence: 76%

Section: Introductionmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 74%

Section: Analytical Modelmentioning

confidence: 82%

See 2 more Smart Citations

Study on propagative collapse of a vapor film in film boiling (mechanism of vapor-film collapse at wall temperature above the thermodynamic limit of liquid superheat)

Ohtake

Koizumi

2004

International Journal of Heat and Mass Transfer

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“…Other researchers have used variations of this probe. Narazaki et al (1989 and1996) have shown results comparing the performance of flat-end, rounded-edge and hemispherical-end cylindrical probes cooled in an agitated bath. Based on the reproducibility of the cooling curves they concluded that the best probe would be that with the hemispherical-end.…”

Section: Introductionmentioning

confidence: 99%

Fluid Dynamics Around Flat-End Cylindrical Quench Probes Under Isothermal and Non-Isothermal Conditions

Cervantes¹

2018

Rev. Mex. Ing. Quim.

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The most common methodology to describe the complex phenomena occurring during quenching operations is based on measuring cooling curves inside metal test probes instrumented with thermocouples. There are many variants regarding specimen shape, although the preferred shape is a flat-end cylindrical probe. However, mathematical and physical modeling studies, carried out under isothermal conditions, regarding the hydrodynamic behavior of the quenchant around flat-end cylindrical probes suggest that this type of probe should not be recommended for studies quenching. In this paper, we study fluid dynamics around an instrumented flat-end cylindrical probe, both under isothermal (un-heated probe) and non-isothermal conditions (probe heated to 900 ºC and cooled in water at 60 ºC). For this purpose, water at 60°C was used as cooling fluid; three free-stream water velocities (0.2, 0.4 and 0.6 m/s) were studied. Visualization techniques using a high-speed camera and optical filters were applied to characterize the flow around the probe and, at the same time, thermal histories were measured within the probe. The results show that fluid dynamics under non-isothermal conditions is very different from that under isothermal conditions; therefore, it is not advisable to directly correlate fluid dynamics around metal probes characterized under isothermal conditions with cooling curves or the evolution of the wetting front during an actual quench. Keywords: quenching, cooling curves, flat-end cylindrical probe, wetting front, fluid dynamics. ResumenLa metodología más común para describir los fenómenos complejos que ocurren durante las operaciones de temple se basa en la medición de curvas de enfriamiento. Existen variantes de la forma de la probeta, aunque la forma preferida es cilíndrica de base plana. Sin embargo, estudios de modelado físico y matemático realizados en condiciones isotérmicas respecto al comportamiento hidrodinámico del fluido de temple alrededor de las probetas cilíndricas de base plana, sugieren que este tipo de probetas no es recomendable para estudios de temple. En este artículo, se estudia la dinámica de fluidos alrededor de una probeta cilíndrica de base plana bajo condiciones isotérmicas (probeta sin calentar) y no-isotérmicas (probeta calentada a 900 ºC y enfriada en agua a 60 ºC). Para este propósito, se usó agua a 60°C como fluido de enfriamiento; se estudiaron tres valores de velocidad de corriente libre (0.2, 0.4 y 0.6 m/s). Se utilizó una cámara de alta velocidad y filtros ópticos para caracterizar el flujo alrededor de la probeta y, al mismo tiempo, se midieron historias térmicas al interior de la misma. Los resultados muestran que la dinámica de fluidos en condiciones no-isotérmicas es muy diferente a la que ocurre en condiciones isotérmicas; por consiguiente, no es aconsejable correlacionar la dinámica de fluidos en condiciones isotérmicas, con curvas de enfriamiento o con el frente de mojado en un temple real. Palabras

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A Brief Review on Test Systems Using a Ball Probe for Determination of Cooling Characteristics of Quenchants

Arimoto¹

2020

J. of Materi Eng and Perform

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A wide variety of test systems have been developed to determine the cooling characteristics of quenchants. Among them, rational systems with good reliability and cost performance have been adopted as domestic and international standards. This review mainly focuses on test systems using a small ball probe and discusses their development processes, features, and potential uses. Although a test system with a ball probe is not defined in current standards, it is known that specific ones used in the past contributed to enhancing the test. This literature survey found a classic test system with 7-mm-dia. silver or 4-mm-dia. chromiumnickel balls, which was created rationally for using the lumped heat capacity method, and was applied to a variety of quenchants at the Kaiser Wilhelm Institute from 1928 to 1931. The institute finally increased the diameter of the silver ball probe to 20 mm due to manufacturing problems and applied it to various quenchants, which was widely applied until the ISO 9950 standard using an Inconel cylindrical probe was established. In latter half of this report, prototypes of the test system using a small ball probe created by the authorÕs group since 2011 were briefly reviewed. This work solved the problem in the previous small ball probes with the current technology. The latest prototype uses a 4-mm-dia. platinum ball probe with a 0.25mm-dia. sheathed thermocouple inserted into the center. The probe heated radiantly in a fixed state with halogen lumps is cooled in the quenchant in the container which is elevated by an electric linear actuator for robotics. This container movement creates a simple relative flow of quenchant around the probe, which has not been seen in the previous test systems. The use of the small ball probe has realized the compact and short-term test system. Keywords ball probe, cooling analysis, inverse heat conduction problem, lumped heat capacity method, quenchant This article is an invited submission to JMEP selected from presentations at the 30th Heat Treating Society Conference and Exposition held October 15-17, 2019, in Detroit, Michigan, and has been expanded from the original presentation.

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Effects of Specimen Geometry on Characteristic Temperature during Quenching of Heated Metals in Subcooled Water

Cited by 10 publications

References 4 publications

Study on propagative collapse of a vapor film in film boiling (mechanism of vapor-film collapse at wall temperature above the thermodynamic limit of liquid superheat)

Study on propagative collapse of a vapor film in film boiling (mechanism of vapor-film collapse at wall temperature above the thermodynamic limit of liquid superheat)

Fluid Dynamics Around Flat-End Cylindrical Quench Probes Under Isothermal and Non-Isothermal Conditions

A Brief Review on Test Systems Using a Ball Probe for Determination of Cooling Characteristics of Quenchants

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