High-pressure sour natural gas transmission — onshore trunk lines and gathering systems in Nigeria.
This repeat supply represents ZC Steel Pipe's multi-year relationship with a Nigerian gas infrastructure operator, delivering 6,000 pieces of 6″ SCH 160 X70Q PSL2 with sour service qualification across two shipment cycles from 2023 to 2025. Repeat orders of this size validate the consistency of ZC's heat chemistry, mechanical testing, and 3LPE coating quality across production batches.
Why 6″ SCH 160 at X70Q? Schedule 160 wall at 18.26 mm is a demanding specification for 6″ pipe — selected when high-pressure service (above 250 bar operating pressure) must be combined with the X70 minimum yield of 485 MPa. The X70Q (quench-and-temper) designation ensures yield uniformity across the wall cross-section, critical for thick-wall fatigue performance in cyclic pressure service.
Sour service qualification (API 5L Annex H): Sour natural gas fields in Nigeria require NACE TM0284 HIC (hydrogen-induced cracking) test compliance and controlled chemistry per Annex H — restricting carbon equivalent and sulfur content to prevent hydrogen blistering under wet H₂S exposure. Standard X70Q PSL2 without Annex H is insufficient for fields above the NACE MR0175 partial pressure threshold.
3LPE coating (DIN 30670): Fusion-bonded epoxy primer + adhesive + extruded polyethylene topcoat at 3 mm thickness delivers long-term cathodic disbondment resistance for direct-burial installation in Nigerian soil conditions with variable moisture and chloride content.
ZC Steel Pipe supplies HIC-tested, Annex-H-qualified X70Q from 2″ to 24″ OD with 3LPE, FBE, or bare finish for Nigerian and West African pipeline operators.