Rapid Induction Heating for Sustainable Manufacturing of Advanced High Strength Sheet Steels for Automotive Applications

Electrification of annealing lines through induction heating technology is a key strategy for reducing carbon emissions and advancing sustainable manufacturing in the steel industry. This study evaluates the feasibility of replacing conventional gas-fired furnaces in continuous annealing lines with induction heating systems, which enable flash annealing and can improve mechanical properties in certain steel grades. Induction annealing, simulated both experimentally and computationally, was compared with conventional continuous annealing to study the effects on microstructural development and mechanical properties. This study focuses on advanced high strength steels and investigates two medium Mn (3–5 wt%) steels designed for quenching and partitioning (Q&P). Heat treatment cycles, including conventional Q&P processes and industrially viable rapid induction annealing cycles, were conducted using a Gleeble thermomechanical simulator and dilatometry. Microstructural characterization using electron microscopy, electron backscatter diffraction, and the magnetic saturation method revealed that rapid induction heating yielded higher fractions of retained austenite compared to conventionally annealed microstructures, likely due to finer microstructural features and local chemical heterogeneity. Mechanical behavior was assessed by means of uniaxial tensile testing coupled with digital image correlation. Computational simulations using ELTA software inform energy-efficient industrial practices for implementing induction heating in existing continuous annealing lines.