What is an API Pipe?
API Pipes are steel tubes manufactured in accordance with standards set by the American Petroleum Institute (API).
These pipes are purpose-built for the oil & gas industry — materials must withstand high pressure, corrosive environments, mechanical stress, and long-term operation.
Core Standards:
API 5L — Line pipe for energy transportation
API 5CT — Casing & tubing for well construction
API 5DP — Drill pipe for drilling operations
Unlike ordinary carbon steel pipes, API pipes must pass rigorous inspection protocols including hydrostatic testing, Non-Destructive Testing (NDT) , and mechanical performance verification. These stringent requirements make API pipes the industry standard for oilfields, offshore platforms, and long-distance pipeline systems worldwide .
API 5ST Specification
Our API 5ST coiled tubing covers 19.1 mm to 88.9 mm OD, with strict quality control ensuring tensile and yield strength (MPa) meet or exceed industry standards. Welded joints are thoroughly inspected for guaranteed downhole integrity.
| Coiled Tubing Dimensions |
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| Outside Diameter | Wall Thickness mm |
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| mm | 1.9 | 2.0 | 2.1 | 2.2 | 2.4 | 2.6 | 2.8 | 3.0 | 3.2 | 3.4 | 3.7 | 4.0 | 4.4 | 4.8 | 5.2 | 5.7 | 6.4 | 7.0 | 7.1 | 7.6 |
| 19.1 |
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| 25.4 | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● |
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| 31.8 | ● | ● |
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| 38.1 |
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| 44.5 |
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| 50.8 |
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| ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● |
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| 60.3 |
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| ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● |
| 66.7 |
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| ● | ● | ● | ● | ● | ● | ● | ● | ● | ● |
| 73 |
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| ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● |
| 82.6 |
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| ● | ● | ● | ● | ● | ● | ● | ● | ● | ● |
| 88.9 |
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| ● | ● | ● | ● | ● | ● | ● | ● | ● |
Main Types of API Pipes
In procurement, buyers typically classify API pipes into three major categories, each supporting different stages of oil & gas production:
🔵 API 5L — Energy Transportation Line
API 5L pipes are designed for transporting crude oil, natural gas, and petroleum products. These pipelines typically connect production sites to refineries and distribution terminals across long-distance networks.
Typical Grade Specifications:
| Grade | Application |
| API 5L Grade B | Standard service |
| X42, X52 | Moderate pressure |
| X56, X60, X65 | High pressure |
| X70, X80 | Ultra-high pressure |
📌 Higher grades = higher yield strength = greater pressure capacity
Manufacturing Methods:
SMLS (Seamless)
ERW (Electric Resistance Welded)
LSAW (Longitudinal Submerged Arc Welded)
SSAW (Spiral Submerged Arc Welded)
🟢 API 5CT — Casing & Tubing
API 5CT pipes are used in oil & gas wells. Their purpose is to maintain well integrity and ensure safe production.
Pipe Types:
Typical Grades: J55 | K55 | N80 | L80 | P110
⚠️ These pipes must withstand high pressure, temperature variations, and corrosive drilling fluids.
🟡 API 5DP — Drill Pipe
Drill pipe connects the drilling rig to the drill bit, transmitting torque and drilling fluid during operations.
Due to sustained cyclic stress, drill pipes are manufactured from high-strength alloy steel and undergo rigorous fatigue testing 💪.
Applications of API Pipes
API pipes are widely used in industries where safety and reliability are paramount.
⛽ Oil & Natural Gas Transmission Pipelines
Transport oil and natural gas over long distances
Systems require pipes capable of withstanding pressure fluctuations and environmental conditions
API 5L pipes are most commonly used in these applications
🏗️ Oil & Gas Wells
Inside the wellbore, pipes must maintain structural integrity under extreme pressure
Casing protects well structure; tubing delivers hydrocarbons to surface
These systems rely on API 5CT pipes
🌊 Offshore Energy Projects
Offshore pipelines operate in harsh marine environments
Saltwater corrosion, external pressure, and mechanical loads demand pipes with reliable mechanical performance
API pipes are commonly used in subsea pipeline systems
🏭 Petrochemical & Refining Facilities