摘要：Abstract Bead-on-plate friction stir welds were made on {P91} alloy with low and high rotational speeds (100 and 1000 RPM) to study their effects on weld microstructural changes and impression creep behavior. Temperatures experienced by the stir zone were recorded at the weld tool tip. Different zones of welds were characterized for their microstructural changes, hardness and creep behavior (by impression creep tests). The results were compared with submerged arc fusion weld. Studies revealed that the stir zone temperature with 100 RPM was well below Ac1 temperature of {P91} steel while it was above Ac3 with 1000 RPM. The results suggest that the microstructural degradation in {P91} welds can be controlled by low temperature friction stir welding technique.
