Environmental impact assessment and comparative analysis of hot stamping and cold stamping processes: a cradle-to-gate lifecycle assessment study

This manuscript presents the results of a cradle-to-gate lifecycle assessment (LCA) conducted on a component manufactured through two distinct process routes: Hot stamping of AA6082-T6 and cold stamping of AA5251-H22. The primary objective of this study is to provide a detailed understanding of the environmental impact associated with these processes and to conduct a comparative analysis of their environmental profiles. A comprehensive process map was developed for each manufacturing route, delineating all inputs and outputs at each step. Forming trials were executed during the LCA, capturing equipment energy consumption. When immediate data was unavailable from trials, the LCA model was supplemented with information from the Ecoinvent 3.6 database. The analysis demonstrates that the adoption of advanced near-net-shape manufacturing, specifically hot stamping, can significantly diminish the environmental impact compared to traditional cold stamping processes. Despite the additional energy requirements for heating in hot stamping, the overall environmental savings, supported by uncertainty analysis, are considerable. In the case of the examined demonstrator part, hot stamping showcased a noteworthy 35% reduction in CO2 equivalent emissions, equivalent to 6 kg CO2e per part. This reduction is primarily attributed to two key factors: the decreased material thickness achievable in hot stamping while preserving equivalent mechanical characteristics in the final part and the recycling of any material waste after forming. The results underscore the environmental advantages of embracing advanced manufacturing techniques, contributing valuable insights for environmentally conscious decision-making in the manufacturing industry.