Seamless
API 5CT Casing & Tubing
API 5CT seamless casing and tubing in J55 through Q125 — the OCTG specification for surface, intermediate, and production strings in onshore and offshore wells worldwide.
API 5CT OCTG
OVERVIEW
The wellbore integrity specification.
API 5CT is the governing specification for casing and tubing used in oil and gas well construction. It defines the grades (J55 through Q125), connection types (STC, LTC, BTC), testing requirements, and quality systems that every OCTG product must satisfy. Global Seamless manufactures API 5CT seamless casing and tubing with full API monogram certification.
Every joint is drift tested, hydrostatically tested, and non-destructively examined per API requirements. Sour-service grades (L80, C90, T95) are tested to NACE MR0175 with documented HIC and SSC results.
✓ Casing: J55, K55, N80, L80, C90, T95, P110, Q125
✓ Tubing: J55, L80, N80, P110
✓ Connections: STC, LTC, BTC, EUE, NUE, premium
✓ API monogram licensed
✓ NACE MR0175 sour service grades
✓ Tubing: J55, L80, N80, P110
✓ Connections: STC, LTC, BTC, EUE, NUE, premium
✓ API monogram licensed
✓ NACE MR0175 sour service grades
API 5CT seamless casing
DIMENSIONAL SPECIFICATIONS
Available size range.
Cold Drawn Seamless (CDS)
| Grade | Min Yield (MPa) | Max Yield (MPa) | Service |
|---|---|---|---|
| J55 | 379 | 552 | Surface / conductor |
| N80 | 552 | — | Intermediate / production |
| L80 | 552 | 655 | Sour service (NACE) |
| P110 | 758 | 965 | Deep / HP wells |
| Q125 | 862 | 1034 | HPHT wells |
APPLICATIONS & INDUSTRIES
Where these tubes get used.
MATERIAL GRADES
J55 through Q125.
PRODUCTION
N80 · L80
Intermediate and production strings; L80 for sour service per NACE.
DEEP / HPHT
P110 · Q125
High-collapse, high-yield grades for deep and HPHT wells.
TECHNICAL ARTICLES
Latest insights on casing and tubing.
ARTICLE
API 5CT Casing Grade Selection
J55 through Q125 — matching grade to well conditions.
ARTICLE
STC vs LTC vs BTC Connections
Choosing the right casing connection for your well.
RELATED PRODUCTS
Often paired with.
GET A QUOTE
Send your OCTG spec.
Get a proposal in 24 hours.
OD, weight, grade, connection, range, quantity — we revert with a technical & commercial proposal.