AbstractBending applying local induction heating is an efficient way to produce bended pipes of various radii with lower cost and to provide better quality product. In this process, it is very important to control the thickness of the pipe to ensure its performance. The lower thickness usually turned out in outer section of bended pipe, even though controlling the thickness carefully by reverse moment. As the radius of pipe is smaller, especially, the thickness reduction is larger. The reduced thickness becomes a cause of deterioration of properties and confidence of bended pipe. To verify confidence of bended pipe, the fatigue properties were investigated for the bended pipes with small radius of the curvature of 1.5 ∼ 2.0DR. Two bended sections, which were extrados and intrados region, were compared with as-received section about microstructure, hardness, high cycle fatigue and residual stress. Carbon steel showed better fatigue characteristics at bended section than at as-received pipe. Improvement of fatigue strength resulted from both refinement of ferrite grain size and the achievement of a relatively fine pearlite by both plastic deformation and rapid-heating-cooling during pipe bending applying local induction heating. Hardness increased over 20% and fatigue endurance limits of deformed section were enhanced over 10%.