(1) Lamination and Inclusion: When processing the pipe ends, operators should carefully inspect the pipe ends for any lamination or inclusion. Steel pipes are not allowed to have lamination or inclusion that extends to the pipe end or bevel surface with a transverse dimension exceeding 6.4mm. For pipe ends with defects exceeding 6.4mm, additional cutting can be performed until no lamination or inclusion exceeding 6.4mm remains.
(2) Hard Spots: Steel pipes should not have hard spots exceeding 50mm in any direction and with a hardness value higher than 35HRC (327HBW/345HV10). If any, they should be removed.
(3) Bevel and Root Face: Unless otherwise specified by the customer, steel pipes with a wall thickness greater than 3.2mm should be beveled at an angle of 30° to 35°; the root face should be 1.6±0.8mm, with the bevel angle measured from the perpendicular to the axis of the steel pipe. The pipe end bevel should not exceed 1.6mm. For GB/T3091 products and SY/T5037 products with a pipe diameter D ≥ 813mm, the bevel tolerance can be relaxed to 3.0mm. To remove internal burrs caused during pipe end processing, the internal chamfer of the pipe end should not exceed 7°, measured from the centerline of the steel pipe.
