The book contains an analysis of theoretical dependences, bottlenecks and limiting factors of a new technology used in both Consteel and shaft furnaces operating with flat bath. Performances obtained and potentialities of these furnaces are examined. Based on this analysis, a steel melting aggregate of the new type - fuel arc furnace FAF has been developed and offered. In comparison with the best modern electric arc furnaces of identical capacity the productivity of FAF is higher by 36% and electrical energy consumption is lower by a factor of 1.8. Environment characteristics are considerably improved.Flat bath is a revolutionary change of technological process.- Implementation of a new.- Theoretical analysis of both basic dependences and limiting factors of the flat bath technology.- Intensification of melting a scrap in the liquid metal.- High-temperature preheating a scrap.- Satisfying environmental regulations.- Fuel arc furnace (FAF) as a steel melting unit of proximate future.