U-bent are widely used in heat-exchanger systems. Heat-exchanger equipment on the basis of seamless stainless U-tubes is essential in strategically important and critical fields nuclear and petrochemical machine building.
 
Heat treatment:
 Stress relive annealing of U-tubes after bending only for all positions
Surface condition finished U-tube shall be free of scale,without scratches after bending.
through ball test
Eddy Current tests.
Hydrostatic tests after bending
Bending radius as per your drawings
Dimensional tolerances as per standards
Flattening at the bend should not exceed ten percent of the norminal tube outerside.