Surface residual stresses as well as wall thickness and ovality changes after U-bending process on UNS N06690 row-1 heat exchanger tubes, were estimated. Surface residual stresses were measured by Hole Drilling Method(HDM), calculating the stresses from relieved strains of 3 rosette strain gages. After bending of the tubes, dimensional tolerances for wall thickness and ovality were satisfied with ASTM requirements. Residual stresses at the extrados were introduced with compressive stress(-) by bending operations, and its maximum value reached-319 MPa in axial direction at ${phi}=0^{circ}$ in position. Tensile residual stresses(+) of ${sigma}_zz=45$ MPa,${sigma}_zz=25$ MPa were introduced in the intrados surface at position of ${phi}=0^{circ}$ Maximum tensile residual stress of 170 MPa was detected on the flank side at position of ,${phi}=95^{circ}$i.e., at apex region. It appeared that higher stress gradients were generated at the irregular transition regions. In the trend of residual stress changes with U-bend position, the extrados is related with the changes of ovality and the intrados is related with the changes of wall thickness.