TY - JOUR T1 - Influence of rotational speed on the development of microstructure in a friction stir welded 304 austenitic stainless steel TT - تاثیر سرعت چرخشی ابزار در شکل‌گیری ریزساختار در مقاطع جوش فولاد زنگ‌نزن آستنیتی 304 حاصل از فرایند جوشکاری همزن اصطکاکی JF - JWSTI JO - JWSTI VL - 6 IS - 1 UR - http://jwsti.iut.ac.ir/article-1-290-en.html Y1 - 2020 SP - 1 EP - 8 KW - Friction stir welding KW - Stainless steels KW - Dynamic recovery KW - Dynamic recrystallization KW - Shear texture N2 - Friction stir welding was conducted on AISI 304 austenitic stainless steel sheet with dimensions of 100 mm × 100 mm × 2 mm. The FSW was performed at a welding speed of 150 mm/min and rotational speeds of 400 and 800 rpm. The results showed that high frequency of low angle grain boundaries (LAGBs) were formed through dynamic recovery in the thermo-mechanically affected zone (TMAZ). Higher amount of LAGBs were developed in the TMAZ of welded sample with 800 rpm due to the higher amount of strain and heat generated. High fraction of high angle grain boundaries were formed in the stir zone (SZ) of the welded samples through the occurrence of continuous dynamic recrystallization (CDRX). A very fine microstructure developed in the sampled welded with lower rotational speed. Analysis of texture using {111} Pole figures showed the formation of shear texture components in the SZ of both welded samples. The intensity of the obtained texture for the sample welded with 800 rpm was greater. The formation of shear texture components in the SZ of both samples implied the occurrence of CDRX mechanism M3 ER -