Influence of Hot-Dip Galvanizing Cooling Process on Properties of 1000 MPa Multiphase Steel

J.P. Wang , Y.J. Fu, Y. Chen, H.L. Liu, L.W. Zhang, and J.L. Bai

DOI: https://doi.org/10.64486/m.65.2.9
Online publication date: December 8, 2025

Abstract: For 1000 MPa multiphase steel CP980+Z, simulation experiments were carried out under different slow-cooling and rapid-cooling temperatures, and the resulting mechanical properties and microstructures were evaluated. The findings show that this work fills a gap in previous research on CP980+Z. Unlike earlier studies that focused on austenitization temperature or cold rolling reduction, this study systematically reveals the synergistic regulation mechanism of slow cooling in the intercritical region and rapid cooling on the material’s overall performance. When the slow-cooling temperature ranges from 740 °C to 760 °C, the yield ratio meets the required standards. When the final rapid-cooling outlet temperature is 350 °C, the strength–ductility balance and hole expansion capability reach optimal values. The underlying microstructural mechanism is governed by controlling ferrite nucleation and growth during slow cooling, and bainite–martensite transformation during rapid cooling. This combined control determines the content and distribution of martensite and martensite/austenite (M/A) islands.

Keywords: slow cooling temperature; rapid cooling temperature; galvanized multiphase steel; bainite

This article is published online first and will appear in Metalurgija, Vol. 65, Issue 2 (2026).