Low silicon bainite cast irons are most advanced and promising structural materials. Due to their high technological plasticity these alloys can be used for parts production by casting and hot plastic deformation. This results in a structure refinement, reduced wastage, pores elimination and increased productivity. Therefore, these materials withstand range of external technological processes (thermal-mechanical treatment, isothermal heat treatment) aimed at forming in cast irons new structural properties, which increase their performance (strength, fracture resistance, wear resistance under dry and abrasive friction) This work studied processes of austenite formation and austenite decomposition in low silicon-aluminium cast irons. Temperature-time dependence on the formation of bainite and martensite structures in these alloys was identified. Active influence of aluminium on the phase composition of cast irons after heat treatment was defined. Based on data obtained, a preliminary plastic deformation of these alloys extends the process control of structural modification during subsequent isothermal heat treatment.