Effect of Bath Temperature on Cooling Performance of Molten Eutectic NaNO3-KNO3 Quench Medium for Martempering of Steels

Rao, K. M. Pranesh; Prabhu, K. Narayan

doi:10.1007/s11661-017-4267-7

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…The changes in the mean heat flux at critical points are primarily caused by the multiple thermal stability regimes that emerge when molten salt mixtures approach these critical points. These changes in thermal stability induce variations in heat flow and surface temperature because they give rise to chemical processes that release or absorb heat. , …”

Section: Resultsmentioning

confidence: 99%

“…These changes in thermal stability induce variations in heat flow and surface temperature because they give rise to chemical processes that release or absorb heat. 9 , 10 …”

Section: Resultsmentioning

confidence: 99%

“…The term T ( P ts ) was determined considering four upcoming time intervals during which the heat flux remained consistent. The conjugate gradient method-based inverse algorithm developed by Pranesh Rao and Prabhu 10 was used to determine the spatially dependent transient heat flux at the metal–quenchant interface. The current work used the same method.…”

Section: Heat Flux Evaluationmentioning

confidence: 99%

“…Contrary to popular opinion, film boiling provides poor cooling rates throughout the quench heat transfer. Pranesh Rao and Prabhu 10 incorporated the inverse heat transfer technique to determine the transient quench heat flux that was spatially based. Their aim was to explore how effectively and uniformly the molten eutectic NaNO 3 –KNO 3 mixture cools at varying temperatures in the quenching bath.…”

Section: Introductionmentioning

confidence: 99%

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Heat Transfer of Ca (NO₃)₂-KNO₃ Molten Salt Mixtures for Austempering and Martempering Processes of Steels

Quadros,

Khan,

Mohin

et al. 2024

ACS Omega

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Molten salts are highly effective as a quenching medium for austempering and martempering processes, enabling precise control of cooling rates to achieve the desired microstructures and mechanical characteristics in steel components. One such promising molten salt is a multicomponent Ca (NO 3 ) 2 -KNO 3 molten salt. The current work explores the cooling severity of molten Ca (NO 3 ) 2 -KNO 3 mixtures, which are commonly used for such purposes. The said mixture, with varying concentrations and bath temperatures was used for quenching the Inconel probe with thermocouples. The temperature data extracted was used to determine the transient heat flux developed at the metal−quenchant interface. A set of critical points were assessed against the peak heat extraction rates. Additionally, the fluctuation of mean heat flux and surface temperature in relation to these crucial points were plotted, along with changes in composition and bath temperature of the quench media. The cooling intensity of these quench solutions, as measured by Inconel probes, correlated well with the average hardness values observed in steel probes. The level of homogeneity in heat transmission, as measured by the spatial variance of the normalized heat energy, decreased as the percentage of KNO 3 in the quench medium increased.

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Section: Resultsmentioning

confidence: 99%

“…These changes in thermal stability induce variations in heat flow and surface temperature because they give rise to chemical processes that release or absorb heat. 9 , 10 …”

Section: Resultsmentioning

confidence: 99%

Section: Heat Flux Evaluationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Heat Transfer of Ca (NO₃)₂-KNO₃ Molten Salt Mixtures for Austempering and Martempering Processes of Steels

Quadros,

Khan,

Mohin

et al. 2024

ACS Omega

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“…In addition, they also compared predicted and experimental phase transformation curves. K.M.Pranesh Rao et al [19][20][21] calculated the instantaneous heat flux of the quenching interface by using the temperature data obtained from the quenching experiments of samples with different salt temperatures and different molten salts. By comparing this with the oil quenching process, it is found that only nucleate boiling heat transfer and convective heat transfer occur in the salt bath heat-treating process.…”

mentioning

confidence: 99%

A Novel Design of a Molten Salt Bath Structure and Its Quenching Effect on Wire Transformation from Austenite to Sorbite

Li,

Wang,

Zhang

2024

Metals

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The technology for obtaining sorbite by isothermal quenching of high-temperature molten salt has been used by more and more factories to produce wires with high tensile strength. In this paper, the controlling cap and bottom pipeline of the original salt bath are redesigned. The mathematical model previously proposed is used to simulate the redesigned salt bath model, and the flow field is analyzed in detail. The redesigned and original controlling cap are compared in detail by applying third-generation vortex identification technology. Then, by using the inverse heat transfer method, the heat transfer coefficient (HTC) during the boiling heat transfer stage of the wire rod in molten salt is calculated by taking advantage of quenching experimental data, on the basis of which the original model is corrected. Finally, a new salt bath design is proposed, which divides the salt bath into two parts. The first salt bath at 515 °C is used to cool the austenitized wire and complete the initial phase transformation. The second salt bath at 560 °C is used to prevent the transformation from retained austenite to bainite, and to induce its transformation from retained austenite to sorbite.

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Effect of Inflow Mode and Parameters on Temperature and Phase Transition of Wires During Isothermal Quenching in Molten Salt Bath

Li,

Wang,

Xing

et al. 2023

Metall Mater Trans B

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Effect of Bath Temperature on Cooling Performance of Molten Eutectic NaNO3-KNO3 Quench Medium for Martempering of Steels

Cited by 12 publications

References 8 publications

Heat Transfer of Ca (NO₃)₂-KNO₃ Molten Salt Mixtures for Austempering and Martempering Processes of Steels

Heat Transfer of Ca (NO₃)₂-KNO₃ Molten Salt Mixtures for Austempering and Martempering Processes of Steels

A Novel Design of a Molten Salt Bath Structure and Its Quenching Effect on Wire Transformation from Austenite to Sorbite

Effect of Inflow Mode and Parameters on Temperature and Phase Transition of Wires During Isothermal Quenching in Molten Salt Bath

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Effect of Bath Temperature on Cooling Performance of Molten Eutectic NaNO3-KNO3 Quench Medium for Martempering of Steels

Cited by 12 publications

References 8 publications

Heat Transfer of Ca (NO3)2-KNO3 Molten Salt Mixtures for Austempering and Martempering Processes of Steels

Heat Transfer of Ca (NO3)2-KNO3 Molten Salt Mixtures for Austempering and Martempering Processes of Steels

A Novel Design of a Molten Salt Bath Structure and Its Quenching Effect on Wire Transformation from Austenite to Sorbite

Effect of Inflow Mode and Parameters on Temperature and Phase Transition of Wires During Isothermal Quenching in Molten Salt Bath

Contact Info

Product

Resources

About

Heat Transfer of Ca (NO₃)₂-KNO₃ Molten Salt Mixtures for Austempering and Martempering Processes of Steels

Heat Transfer of Ca (NO₃)₂-KNO₃ Molten Salt Mixtures for Austempering and Martempering Processes of Steels