Development of a Localized Heat Treatment Route for Stamped Automotive Parts

The increasing demand for sustainable and space-efficient manufacturing solutions in the automotive industry has driven the search for alternative processes to conventional hot stamping. This study proposes a novel localized heat treatment technique based on Joule heating, aiming to reduce the physical footprint of production equipment, simplify the thermal processing of structural components, and minimize the carbon footprint of the process. The method consists of cold stamping followed by localized austenitization of 22MnB5 steel using electrically powered copper electrodes, eliminating the need for large-scale gas-fired furnaces. The process is particularly advantageous in the Brazilian context, where the electric energy matrix is predominantly hydroelectric, contributing to lower CO2 emissions. Experimental trials were conducted using a Gleeble® thermomechanical simulator to optimize thermal cycle parameters (heating rate, austenitization temperature, and soaking time) ensuring the formation of a martensitic microstructure in the treated region while preserving the original ferritic-pearlitic structure elsewhere. The resulting microstructural gradient enables localized mechanical properties, with potential application in crash-relevant automotive components. The proposed route demonstrates technical feasibility and industrial relevance, offering a compact and sustainable alternative to conventional hot stamping.