In this study, the effect of rotational speed on the microstructure and weldability of AISI1030 steel and AISI304 stainless steel welded by friction welding method were investigated experimentally. The weld joints were manufactured with rotational speed (1500, 1600, 1700, 1800, 1900, and 2000rev/min.), friction pressure (40MPa), forging pressure (60MPa), forging time (4s), and friction time (6s). After the FW process, the microstructures of the weld interfaces were analyzed by optic microscopy, scanning electron microscopy, energy dispersive spectrometry, elemental mapping, and X-ray diffraction analysis. Moreover, the weld strength was analyzed by tensile test, and the fracture behavior was investigated with scanning electron microscopy. The results indicated that increased rotational speed had a significant effect on the microstructure and weldability.