Acceleration of regeneration treatment for nanostructured bainitic steel welding by static recrystallisation

In order to accelerate bainite transformation during regeneration treatment following nanostructured bainite steel welding, static recrystallisation mechanism is adopted to refine the coarse grain size during two-pass welding. Large mechanical deformation was introduced into the coarse grain zone of the first weld pass, where static recrystallisation would occur with thermal effect of the second weld pass. Static recrystallisation kinetics of nanostructure bainite was studied by two-pass hot deformation experiments. The explicit temperature function of two-pass welding was presented, and effect of welding parameters on static recrystallisation of the deformed coarse grain zone was analysed. Experimental results showed that grains in original coarse grain zone were greatly refined and that nanostructured bainite regeneration was remarkably accelerated.