Annealing twin mechanism for 304 stainless steel solution treatment process

The texture evolution, twin crystallographic nature and grain orientation variation during the solution heat treatment process of the 304 stainless steel pipe were studied. It was found that after the solution heat treatment, the texture type clearly changed, and the texture strength was greatly increased. During the solution heat treatment process, grain boundaries migrated along the orientation available for grain growth, giving rise to abnormal growth of some grains through merging with the adjacent small grains. After the solution heat treatment, more 60 degrees twins formed in the microstructures of the 304 stainless steel pipe, and the fraction of the twin boundaries showed a pronounced increase. Analysis of the twin crystallographic nature of the FCC crystals showed that four kinds of twin variants can be formed within austenite parent grains, and twelve kinds of misorientations can be formed between the austenite parent grains and the secondary twins.