Energy and CO2 emission evaluation of a vacuum gas quenching process

Özdeşlik Beste - Sistem Teknik Industrial Furnaces (Türkiye)

Heat treatment of dies is an important step that provides key performance in the aspect of sustainability of production capacity of the plastic and metal injection sector. The heat treatment of machined die consists of two different stages as hardening and tempering. Hardening is the first step that allows the material fully hardened to the desired hardness level and reorganize the grain structure. In order to make the hardening process in clean environment with minimum distortion while avoiding cracking, vacuum gas quenching furnaces are widely used. This study delineates the system boundaries for vacuum gas quenching process of H13 tool steel with 484.5 kg, scrutinizing temperature profiles, energy, and quenching gas consumption across operational stages within established greenhouse gases scopes. The experiment was conducted by considering the requirements of the commercial heat treatment. For this, 650°C and 850°C were selected as pre-heating temperatures and 1030°C was selected as austenitizing temperature. The cooling phase of the material was expanded until the material temperature was reached to 70°C. It was obtained that the vacuum furnace was used total 4.62 m3 nitrogen during partial pressure heating and cooling phase. On the other hand, during the heating and cooling phase, the energy consumption was calculated per material mass as 0.764 kWh/kg and 0.103 kWh/kg, respectively. A methodical analysis examines CO2 equivalent emissions alterations in line with the carbon border adjustment mechanism (CBAM) framework’s transitional benchmarks. The examination across selected national grids reveals marked variations in Scope 2 emissions, with total specific embedded emission (SEE) which considers the direct and indirect emissions, tCO2eq/kg product ranging from a 0.0002 for Iceland to 0.748 for the Czech Republic. Within the CBAM context, emissions from the vacuum furnace process constitute 8% to 13% of the default total emission values for similar steel products.