API 5CT L80 Casing And Tubing Pipe
API 5CT L80 is a restricted-yield steel grade used for casing and tubing in oil and gas wells. It belongs to Group 2 of the API 5CT specification and is designed primarily for Sour Service (H2S environments) or wells where controlled hardness is required to prevent brittle failure.
There are three main types: L80 Type 1 (carbon/alloy), L80 9Cr (9% Chromium), and L80 13Cr (13% Chromium for high CO2 resistance).
L80 casing and tubing features a yield strength of 552–655 MPa and a collapse resistance of up to 120 MPa, making it suitable for deep wells ranging from 3,000 to 5,000 meters. Click to obtain a free material report and customize a tailored downhole solution!
L80 Identification of Color Bands
API 5CT uses color coding to prevent mixing different grades on-site.
| Steel Grade | Pipe Body Color Band | Coupling Color |
| L80 Type 1 | One Red band + One Brown band | Entirely Red with a Brown band |
| L80 9Cr | One Red + One Brown + One Yellow | Red coupling with Brown & Yellow bands |
| L80 13Cr | One Red + One Brown + One Blue | Red coupling with Brown & Blue bands |
Chemical Composition Table (Mass Fraction %)
L80-9Cr and 13Cr are alloyed for corrosion resistance, while L80-1 is a standard carbon/alloy steel.
| Element | L80 Type 1 | L80 9Cr | L80 13Cr |
| Carbon (C) | ≤ 0.43% | ≤ 0.15% | 0.15% - 0.22% |
| Manganese (Mn) | ≤ 1.90% | 0.30% - 0.60% | 0.30% - 1.00% |
| Phosphorus (P) | ≤ 0.030% | ≤ 0.020% | ≤ 0.020% |
| Sulfur (S) | ≤ 0.030% | ≤ 0.010% | ≤ 0.010% |
| Silicon (Si) | ≤ 0.45% | 0.50% - 1.00% | ≤ 1.00% |
| Chromium (Cr) | - | 8.00% - 10.00% | 12.00% - 14.00% |
Mechanical Properties Table
All L80 types share the same strength requirements.
| Property | Units | Value |
| Yield Strength (Min) | psi (MPa) | 80,000 (552) |
| Yield Strength (Max) | psi (MPa) | 95,000 (655) |
| Tensile Strength (Min) | psi (MPa) | 95,000 (655) |
| Maximum Hardness | HRC | ≤ 23.0 |
| Elongation | % | Calculated based on specimen area |
Dimension and Tolerances
| Item | Tolerance |
| Outside Diameter (OD) | OD < 4-1/2": ±0.031"; OD ≥ 4-1/2": +1.00% / -0.50% |
| Wall Thickness | -12.5% |
| Weight (Single Joint) | +6.5% / -3.5% |
| Weight (Batch/Lot) | -1.75% |
| Length | Range 1: 4.88-7.62m; Range 2: 7.62-10.36m; Range 3: >10.36m |
| Straightness | < 0.2% of total pipe length |
API 5CT L80 Manufacturing Types
Manufacturing Process:
Seamless (S): The most common for L80 to ensure structural uniformity.
Electric Welded (EW): Allowed for L80 Type 1, though less common in critical sour service.
Heat Treatment (Mandatory):
All L80 grades must undergo Quenching and Tempering (Q&T). This process ensures a fine-grained structure and limits the hardness of the steel.
Connection Type, Ends, and Couplings
L80 is often used in gas wells or deep wells, so seal integrity is paramount.
Ends: Typically TE (Threaded & Coupled).
Casing Connections:
STC / LTC: Standard 8-round threads.
BTC: Buttress thread for high tensile loads.
Tubing Connections:
NU: Non-Upset.
EUE: External Upset End (most common).
Premium Connections: For gas-tight requirements in
H2SH2S
wells, "Premium" threads with metal-to-metal seals (e.g., VAM TOP) are frequently used.
Couplings: Must be the same grade (L80) and heat-treated (Q&T).
Reference Inspection for L80
Because L80 is a restricted-yield grade, inspection is more rigorous than for J55/K55:
Hardness Testing (Critical): Mandatory testing to ensure maximum hardness does not exceed 23 HRC. This is the most important test for
H2SH2S
resistance.
NDT (Non-Destructive Testing): 100% Ultrasonic (UT) or Electromagnetic (EMI) inspection to detect cracks or wall thinning.
Hydrostatic Test: Every joint is tested at high pressure to ensure leak-proof performance.
Drift Test: Passing a mandrel through the pipe to ensure internal clearance.
Visual & Dimensional: Checking for surface pits, OD, and wall thickness.
API 5CT L80 OCTG Test Equipments
API 5CT L80 Oil well casing factory
API 5CT L80 Casing and Tubing certificate
FAQ
Are L80 9Cr and L80 13Cr available as welded pipe?
L80 9Cr and L80 13Cr are typically supplied in the form of seamless pipes and are primarily utilized as casing and tubing in oil and gas wells. Given that they must withstand high pressures, elevated temperatures, and corrosive environments (such as conditions containing CO₂ or H₂S), their manufacturing strictly adheres to the API 5CT specification.
Where can the standard scope and PSL requirements for L80 be confirmed?
The scope and PSL requirements for Grade L80 can be verified within the API 5CT standard, covering product types, manufacturing processes, dimensional ranges, and quality levels.
Product Types: Casing, tubing, pup joints, etc.
Manufacturing Processes: Primarily seamless steel pipe; L80 9Cr/13Cr grades are typically not manufactured using welding processes.
Dimensional Range: Outer diameter 114.3–508 mm; wall thickness 5.21–16.13 mm.
PSL Levels:
PSL-1: Basic requirements, suitable for standard operating conditions.
PSL-2: Includes additional requirements for impact toughness and chemical composition control.
PSL-3: The highest level; requires sulfur-resistance certification and is intended for use in extreme environments.
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