ECOHEAT: Energy-Efficient Press Hardening of Thick Patch Blanks for Lighter Car Bodies

ECOHEAT is a research project focused on developing energy-efficient heating strategies for press hardening of thick sheet metal blanks. The project focuses on thick top plates that are used locally to reinforce automotive body components. By combining induction heating with conventional furnace heating in a targeted way, ECOHEAT aims to reduce energy consumption during the press-hardening process by more than 30% while maintaining high component strength.

ECOHEAT investigates whether thick reinforcement panels can be efficiently heated to the austenitizing temperature and then quenched in a way that produces sufficient martensite to achieve the required local strength.

The overall concept combines two key objectives:

• Local reinforcement of areas that are exposed to particularly high loads
• Reduced material usage, since the carrier sheet can be designed with a lower thickness when local reinforcement is provided

This approach is intended to reduce the overall weight of automotive body components without compromising crash performance. By reinforcing high-stress areas locally, thinner carrier sheets can be used, supporting lightweight construction concepts in automotive engineering.

ECOHEAT combines different heating technologies within the press-hardening process:

The project analyzes press-hardenable steels with different coating systems:

A key research objective is to maintain the integrity and performance of the coatings despite rapid and localized heating.

• Energy efficiency: >30% reduction in energy consumption during the heating process for press hardening of top plates
• Crash performance: >10% increase in energy absorption in crash tests of real components with thick top plates
• Simulation and prediction: >5% improvement in prediction accuracy through coupled microstructure-process simulations
• Process stability: Development of induction heating parameters for AlSi- and Zn-coated press-hardened steels

Thick top plates enable the local reinforcement of highly stressed areas of vehicle structures without increasing the weight of the entire component. This approach can reduce material usage and overall component weight, strengthen crash-critical areas, and unlock greater lightweighting potential in automotive design.

At the core of ECOHEAT is a targeted combination of two heating technologies:

• Induction heating – contactless and locally focused
• Conventional furnace heating – provides a uniform baseline temperature

Different coil geometries and process parameters are being investigated to control the heating of thick sheet metal blanks. The objective is to ensure that the material is fully and sufficiently homogenously austenitized, that martensite formation is achieved during quenching in the forming tool, that the AlSi and Zn coatings remain undamaged, and that energy consumption is significantly reduced compared with conventional furnace-only processes.

Fraunhofer IWU has extensive experience in temperature-assisted sheet metal forming and press hardening for lightweight automotive applications.

Duration
September 2026 to August 2028

Coordination
Fraunhofer IWU

Funded by
BMWE through the AiF under the IGF/CORNET program 

Project Partners

• FOSTA
• Fraunhofer IWM
• Kocaeli Chamber of Industry (KSO), Turkey
• Kocaeli University, Turkey