5. bainitic steels

For a given carbon content, the mechanical strength of bainitic steels is intermediate between that of martensitic steels and ferrito-perlitic structures (figure 23 ). Hardening mechanisms are the same as for martensitic grades, without the hardening effect of carbon in solid solution. Indeed, bainite transformation kinetics are slower than those of martensite, which leaves time for a significant fraction of the carbon to precipitate as cementite during transformation, given the very rapid diffusion rate of carbon in iron. The additional hardening compared to ferrite comes from