Microstructural Evolution and Texture Analysis in a Thermomechanically Processed Low SFE Super-Austenitic Steel (Alloy-28)

Microstructural evolution and texture analysis after 80% cold rolling and subsequent annealing in the temperature range of 750-1050 degrees C is surveyed in Alloy-28. This is precisely studied through electron back scattered diffraction and also is declared through elaborating the hardness map. The occurrence of partially recrystallization is clearly evident in the microstructure which was treated 850 degrees C annealing for 30min. The recrystallization process is completed at 950 degrees C even after 3min, but in an inhomogeneous manner, that is, coexistence of relatively large and fine recrystallized grains. This microstructure contains a high volume of special grain boundaries ended to the complete and homogenous recrystallization at 1050 degrees C, where further grain growth is occurred with increasing time. Texture analysis shows the retaining of Goss texture after annealing at 850 degrees C and this component is introduced as the main reason for retarding recrystallization and, therefore, creation of inhomogeneous microstructure. Finally, the specimens processed at 1050 degrees C indicate the alpha-fiber texture due to occurrence of grain growth. The mechanical properties improvement is mainly attributed to the development of S component and also formation of high fraction of annealing twin. Although, predominant the appearance of Goss texture and grain growth are also known as the main reason for deteriorating strength.