STabilized ELectrical Steels for Electric Mobility

ended

Electric mobility is a central theme in the last years EC transport policies. To make possible the introduction of electric vehicles as mass mobility media for goods and people, efficiency of electric motors is one of the main points as it influences car autonomy, general efficiency of traveling, and above all, batteries consumption and CO2 emissions, which can be significantly reduced. Magnetic characteristics of FeSi electrical steels, used in the core of electric machines, together with the machine design, greatly influences the electric motors efficiency. Precipitates in particular are deleterious for the magnetic quality of electrical steels, as negatively interact with grain growth process, preventing the obtainment of optimal grain size, as well as directly interfering with magnetization processes. The innovative project idea is to prevent fine precipitation developing an unconventional chemical composition of the alloy with unusual high concentration of Ti, V, Nb, (up to 0.1-0.2%). These elements can act as “scavengers” for N and C, main source of fine precipitation, capturing them in coarse precipitates which are believed to be less detrimental for the magnetic steel performances. Ti, V, Nb are added in stainless steel to precipitate C and/or N and to avoid the precipitation of Cr carbides and/or carbonitrides, which deteriorates the steel corrosion resistance. They are also used in IF steels to precipitate C and/or N in Ti-Nb-V carbonitrides, preventing their presence in the lattice as interstitial elements, which deteriorate the draw-ability of the steel. Even if the stabilization of steel by Ti, V, Nb, is used in the steel sector, it is rarely encountered in literature for electrical steels. Optimizing chemical composition and processing conditions, precipitation can be drastically decreased and magnetic characteristics improved allowing European steel producers to obtain high quality steels for efficient electrical mobility in a competitive market.