OCTG
API casing and tubing grades span general-service through higher-strength and controlled-service families. Sour-service suitability must be confirmed from the complete environment and ordered requirements.
RESOURCES
Standards & Grade Guides
Clear reference material connecting common standards and grades with their practical applications.
OAK TECHNICAL REFERENCE
Use the standard to define the product—not as a substitute for the purchase specification.
Standards organize product forms, dimensions, grades, manufacture and verification. A valid enquiry must also state the applicable edition, service conditions and purchaser requirements. Similar strength levels or grade names are not automatically interchangeable.
PRODUCT STANDARD MAP
Connect each tubular product with its governing framework.
The table is a procurement navigator. Final compliance and availability are confirmed against the applicable edition and agreed order documents.
| Product family | Primary framework | Related reference | Common grade families | Product |
|---|---|---|---|---|
| Casing & tubing | API 5CT / ISO 11960 | API 5B for API thread forms | H40 · J55 · K55 · N80 · L80 · C90 · R95 · T95 · P110 · C110 · Q125 | View → |
| Drill pipe | API 5DP / ISO 11961 | API 7-2 for rotary-shouldered connections | E75 · X95 · G105 · S135 | View → |
| HWDP & drill collars | API 7-1 / ISO 10424-1 | API 7-2 connection interfaces | Material and strength requirements by component and order | View → |
| Line pipe | API 5L / ISO 3183 | GB/T 9711 and project specifications | B / L245 through X70 / L485; higher grades subject to route review | View → |
| LSAW & structural pipe | ASTM A671/A672 · EN 10217 · EN 10219 · EN 10210 | GB/T 3091 · GB/T 30063 | Q235 / Q355 and S235 / S275 / S355 / S420 / S460 families | View → |
GRADE FAMILIES
Strength is only one part of material selection.
Chemistry, heat treatment, hardness, toughness, product form and acceptance rules must be reviewed together.
Drill string
E75, X95, G105 and S135 identify common drill-pipe strength families. Tool-joint material, connection, hardbanding and inspection remain separate order inputs.
Line pipe
B/L245 through X70/L485 are common project grades; higher-strength entries require confirmation of diameter, wall, manufacturing route, delivery condition and project acceptance.
Structural & pressure pipe
Q-series and EN S-series designations belong to their own standards. A strength comparison alone does not establish equivalence across GB/T, ASTM or EN systems.
SELECTION RULES
Compare the full specification before proposing an alternative.
Any substitution requires a clause-by-clause review and approval by the responsible purchaser or design authority.
Product context
Confirm that both grades apply to the same product form, dimensional range and manufacturing route.
Material definition
Compare chemistry, heat treatment, mechanical properties, hardness and toughness—not yield strength alone.
Verification basis
Compare sampling, test frequency, specimen location, NDT, acceptance and documentation requirements.
STANDARD & GRADE RFQ CHECKLIST
Send the complete technical basis.
These six inputs let OAK organize a responsible standard, grade and manufacturing-route review.
Request a Technical Review- 01Governing standard and edition
- 02Product form and manufacturing route
- 03Complete grade and delivery condition
- 04Dimensions, tolerances, length and quantity
- 05Service environment and design requirements
- 06Testing, inspection, documents and delivery
START A CONVERSATION
Have a specification or product list?
Send it to OAK PIPE for technical and commercial review.