API J55 Casing
Data verifiedJ55 is the general-purpose API 5CT casing grade for shallow to medium-depth wells with mild service conditions. API 5CT controls its strength band rather than its chemistry, so J55 pipe is a carbon-manganese steel of mill-selected analysis.
Chemical composition
| Element | Content (%) |
|---|---|
| P | ≤0.030 |
| S | ≤0.030 |
| Note | API 5CT sets no C/Mn limits for J55 — chemistry is mill practice |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Yield strength | 379–552 MPa (55–80 ksi) |
| Tensile strength | ≥517 MPa (75 ksi) |
| Density | 7.85 g/cm³ |
Heat treatment
As-rolled or normalized at the mill’s option; supplied as casing/tubing with API threads (STC/LTC/BTC).
Equivalent grades
| Standard | Designation |
|---|---|
| aisi | API 5CT J55 |
| gb | J55 (GB/T 19830) |
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Surface and intermediate casing, water-well casing, low-pressure oil and gas wells.
Processing: Weldable, but casing strings are threaded, not welded — specify the API connection and coupling grade with the order.
FAQ
- Why does J55 have no carbon limit?
- API 5CT specifies J55 by strength and performance tests only (except P/S caps). The mill chooses a chemistry that meets the 379–552 MPa yield window.
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Ask for a quotationVisit NasteelSource: API 5CT published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.