Microstructure Control of Dual-Phase Steels through Hot-Dip Al-Mg-Si Alloy Coating Process

摘要

This study investigates the γ→α transformation kinetics of Fe-Mn-C dual-phase steels at a temperature above the melting point of an Al-8.2Mg-4.8Si (wt.%) alloy coating formed on their surface by hot-dipping process. Using an experimentally determined time-temperature-transformation (TTT) diagram for a model steel of Fe-1.5Mn-0.1C (wt.%), the volume fraction of martensite is controlled through the intercritical heat treatment incorporated into the hot-dipping process. The microstructural observations confirm that this combined process route makes it possible to fabricate hot-dipped Al alloy-coated dual-phase steels with a controlled microstructure.