Uses: Casing, tubing, drill pipes, and surface flow lines for well construction and fluid transport.

Key characteristics: High pressure resistance, fatigue strength, and corrosion resistance.

Steel grades: API grades (H40, J55, K55, N80, L80, C95, P110) and non-API grades . Numbers indicate minimum yield strength in ksi.

Specifications: OD from 26.7 mm to 508 mm. Lengths: R1 (4.88–7.62 m), R2 (7.62–10.36 m), R3 (10.36–14.63 m). All pipes undergo hydrostatic, load, and non-destructive testing.