This allows the formation of bainite, an austenite decomposition product. There are not nearly as many low angle boundaries between laths in lower bainite. They are also added to avoid formation of carbide in the bainite region. Normalized steel consists of pearlite, martensite and sometimes bainite grains, mixed together within the microstructure. Higher contents of silicon and/or aluminium accelerate the ferrite/bainite formation. The fraction of bainite that could form increased as the temperature decreased. A semi-tempered middle ring of martensite and bainite, and 3. However, in martempering, the goal is to create martensite rather than bainite. In lower bainite, cementite nucleates on the interface between ferrite and austenite. Plates of bainite can therefore be smaller than those of martensite in the same steel. If cooled even faster, bainite will form. In normalizing, both upper and lower bainite are usually found mixed with pearlite. Depending on the holding-temperature, austempering can produce either upper or lower bainite. Bainite can essentially be regarded as martensite that tempers during the course of transformation.