Spiral steel pipe main quality indicators

Project

Steel pipe

API Spec 5L

GB/T9711-1997

SY/T5037-2000

Pipe end diameter 
deviation

+2.38mm
-0.79mm

+2.38mm
-0.79mm

D <508 ± 0.75% D or ± 2.5 take a small value 
D ≥ 508 ± 0.50% D or ± 4.5 take a small value

Thickness Tolerance

D <508 +15.0% 12.5% t-t 
D ≥ 508 +19.5% 8.0% t t-

D <508 +15.0% 12.5% t-t 
D ≥ 508 +17.5% 10.0% t t-

D <508 ± 12.5% t 
D ≥ 508 ± 10.0% t

Weld reinforcement

≤3.18mm

≤3.18mm

t ≤ 12.5 　t ≤3.2mm
t> 12.5 　t ≤4.8mm

Straightness

≤ 0.2% L

≤ 0.2% L

≤ 0.2% L

Pipe end state

Bevel 30 ° - 35 ° 
Dayton edge 1.59 ±0.79mm
Cut diagonally ≤1.59mm

Bevel 30 ° - 35 ° 
Dayton edge 1.59 ±0.79mm
Cut diagonally ≤1.59mm

Bevel 30 ° - 35 ° 
Dayton edge 1.59 ±0.79mm
Cut diagonally ≤1.59mm

With the roundness

D> 508 ± 1.0% D

D> 508 ± 1.0% D

D> 508 ± 1.0% D

NDT

100% X -rays, or 100% of the ultrasonic plus pipe end X-ray inspection.

Away from the pipe end203mmRadiographic inspection of welds within; away from the pipe end203mmOutside welds using ultrasonic inspection; rival welds, welding and circumferential welds using ultrasonic inspection

Welding seam, circumferential weld and weld head using X-rays or ultrasound test. Should be carried out on the original welds 100% X-ray or ultrasonic inspection or spot checks

Hydrostatic test

P = 2St / D

P = 2St / D

P = 2St / D

Remark

        D: nominal pipe diameter , mm 　　　　　　t: nominal pipe wall thickness , mm 
        S: hydrostatic test stress , Mpa 　　　　　　P: hydrostatic test pressure , Mpa 
        L; single pipe length, mm