Redução de energia no processo de tratamento térmico t6 nas ligas de alumínio AC2B – AlCuSi

Abstract

The use of aluminum alloys by the automotive industry is one of the main vectors for automakers to achieve important and sustainable goals that define the limits of pollutant gas emissions, fuel consumption, safety and performance. Since aluminum has approximately 1/3 of the density of steel and excellent mechanical properties, replacing steel alloys with aluminum alloys results in a reduction in vehicle weight, positively impacting the listed aspects. There is a relationship defined in some bibliographies that a 10% reduction in vehicle mass can reduce up to 8 g of CO2 per km driven and up to 6.5% in fuel consumption. However, for the application of these changes to be viable, a high degree of innovation is necessary in traditional alloys, which, in turn, require a high consumption of electrical energy for their processing, as aluminum is present in nature in the form of an oxide. called alumina (Al2O3), which is obtained through the reduction of bauxite ore by electrolysis, where around 2000°C is required for the process, which consumes large amounts of energy, on the order of 15 kWh/kg of aluminum (50 to 55 MJ/kg) in steel mills, leaving the industry with only the possibility of reducing energy in fusion processes and heat treatments. At the same time, aluminum alloys of the 2XXX series, whose main element is copper, are the alloys most used in the aerospace and automotive industries in the manufacture of suspension components, forged wheels, engine heads, aircraft fuselages, etc. as they are mostly heat treatable alloys, and after treatments, resistance of 450 MPa can be reached. However, one of the challenges in meeting cost and environmental targets is the high energy consumption to melt and heat treat these mechanical components. In this way, this dissertation aims to provide a 30.7% reduction in time in the artificial aging stage of T6 heat treatments applied to AC2B alloy, AlCuSi alloy through proposals that change the ranges of alloy elements Cu, Si and Mg without compromising the mechanical properties of the material by optimizing the solubility of hardening precipitates in a shorter period of time, thus reducing electrical energy consumption and CO2 production in the process by 14.6% and 2.99% of Cu in the cost alloy manufacturing.