Effect of Cooling Rate on the Precipitation Behavior of MnS Inclusions in 46MnVS5 Non-Quenched and Tempered Steel

H.K. Sun, Y.H. Li, P. J. Li, S.H. Wang, B. X. Lu, and Y.K. Xue 1

DOI: https://doi.org/10.64486/m.65.4.1
Online publication date: February 06, 2026

Abstract: This study systematically investigated the effects of cooling rates on the morphology, size, distribution, and microstructural properties of MnS inclusions in 46MnVS5 non-quenched and tempered steel through three cooling methods: water quenching, air quenching, and furnace cooling. Results indicate that cooling rate significantly regulates MnS precipitation behavior: under furnace cooling, MnS forms coarse particles that aggregate along grain boundaries, leading to reduced properties; air cooling produced spherical or short rod-shaped MnS with uniform distribution and optimal comprehensive properties; water cooling resulted in fine, dispersed MnS with a martensite/bainite microstructure, enhancing toughness but requiring tempering treatment. A nonlinear relationship between cooling rate and average MnS diameter was established, providing theoretical support for optimizing air cooling processes.

Keywords: non quenched and tempered steel; cooling rate; MnS inclusions; microstructure

This article is published online first and will appear in Metalurgija, Vol. 65, Issue 4 (2026).