Journal Published Online: 14 June 2022
Volume 11, Issue 1

A Novel LiNO -Based Eutectic Salt Mixture for Industrial Heat Treatment

CODEN: MPCACD

Abstract

A potassium nitrate–lithium nitrate–sodium nitrate (KNO3-LiNO3-NaNO3) eutectic mixture having a low melting point has been proposed as an alternative high-temperature quench medium. Inconel and steel probes were used to compare the quench performance of a conventional sodium nitrite (NaNO2) eutectic mixture and the proposed alternative medium at different bath temperatures. For the Inconel probe, the heat extraction rate was higher in the eutectic LiNO3 mixture maintained at 150°C. At elevated bath temperatures of 200°C, 250°C, and 300°C, the heat extraction rate was higher in the eutectic NaNO2 mixture. AISI 52100 steel probes quenched in eutectic LiNO3 quench medium at 150°C and 200°C showed higher hardness. At bath temperatures of 250°C and 300°C, the hardness of AISI 4140 steel probes quenched in both media was comparable. Wettability studies on Inconel and steel surfaces revealed the occurrence of nonuniform dilation of a LiNO3 eutectic mixture droplet. On the steel surface, the phenomenon occurred at lower temperatures, which resulted in an extended boiling stage and increased hardness.

Author Information

Pranesh Rao, K. M.
Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Mangalore, India
Prabhu, K. Narayan
Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Mangalore, India
Pages: 11
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Stock #: MPC20220007
ISSN: 2379-1365
DOI: 10.1520/MPC20220007