Grain boundary assembles developed in an austenitic stainless steel during large strain warm working

The evolution of strain-induced grain boundaries in a 304-type austenitic stainless steel during multiple warm forging was studied. The developed grain boundary distributions significantly depended on the processing temperature. The misorientation distribution of deformation boundaries that evolved after total strain of 4 at 500 °C is characterised by a sharp maximum against small angles below 10° and a flat‐type distribution with almost the same fractions for different misorientations for high-angle boundaries. On the other hand, two sharp peaks on the boundary misorientation distribution are developed after processing at 800 °C. One of them corresponds to low-angle subboundaries and the other results from twin boundaries with misorientations of 60°. The difference in the characters of strain-induced grain boundaries is associated with different mechanisms of dynamic recrystallization operating at 500 and 800 °C.

► Submicrocrystalline 304-type steel by multiple forging at 500–800 °C.
► Different distributions of boundary misorientations are developed at 500 and 800 °C.
► Boundary misorientation distribution depends on dynamic recrystallization mechanism.
► Flat-type misorientation distribution for high-angle boundaries develops at 500 °C.
► Sharp peak against 60° on boundary misorientation distribution is involved at 800 °C.