4.1 The longitudinal welds on the same section of a coiled tube should not exceed two; the spacing between the two longitudinal welds should not be less than 200mm.

During the rolling process, the distance between the two longitudinal seams should be greater than 100mm, and the distance from the outer wall of the branch pipe to the weld should not be less than 50mm.

4.3 The misalignment of the inner wall of the tube joint should not exceed 10% of the wall thickness and should not be greater than 2mm.

4.4 The circumference deviation and roundness deviation of the rolled tube shall comply with the specifications in Table 5-2.

The arc length of the caliper plate for the 4.5 rolled tube should be 1/6 to 1/4 of the tube's circumference; the gap between the template and the inner wall of the tube should comply with the following specifications: the longitudinal joint at the对接 should not exceed 10% of the wall thickness plus 2mm, and should not be greater than 3mm. The longitudinal joint 200mm from the tube end should not exceed 2mm. For other sections, the gap should not exceed 3mm.

4.6 The vertical deviation from the end face to the centerline of the coiled pipe shall not exceed 1% of the outer diameter of the pipe or 3mm, whichever is greater. The straightness deviation shall not exceed 1mm/m. For coiled pipes with weld seams that cannot be formed on both sides, a root weld should be applied inside the pipe when the nominal diameter is 600mm or greater.

During the coil processing, prevent surface damage to the sheet metal. Grind away severely damaged areas to achieve a smooth transition, ensuring that the wall thickness at the grinding spot is not less than the designed thickness.

④ The misalignment of longitudinal seams in steel coil pipes should not exceed 10% of the wall thickness, nor should it be more than 1mm; the perpendicular deviation of the coil end face from the centerline should not exceed 1% of the outer diameter of the pipe, nor should it be more than 3mm; the flatness deviation should not exceed 1mm/m; for coil pipes with a diameter greater than 600mm, two longitudinal weld seams are permitted, with a spacing between the seams greater than 300mm; the circumference deviation and ellipticity of the coil pipes should comply with the specifications in the following table: