API 5L Seamless Steel Pipeline
API 5L: Seamless Steel Pipe for Pipeline Transportation Systems
The API 5L specification provides standards for seamless and welded steel pipes for use in pipeline transportation systems in the petroleum and natural gas industries. The specification covers pipes suitable for conveying gas, water, and oil.
Scope
API 5L covers seamless and welded steel line pipe. It includes plain-end, threaded-end, and belled-end pipe, as well as through-the-flowline (TFL) pipe and pipe with ends prepared for use with special couplings.
Key Features
Grades
API 5L includes several grades, each with specific mechanical and chemical requirements. The grades are categorized into two product specification levels (PSLs):
- PSL 1: Standard quality for line pipe.
- PSL 2: Has additional chemical composition and mechanical property requirements.
Common grades include:
- PSL 1 Grades: Grade A, Grade B, X42, X46, X52, X56, X60, X65, X70, etc.
- PSL 2 Grades: X42, X46, X52, X56, X60, X65, X70, X80, etc.
Chemical Composition
The chemical composition requirements vary by grade and PSL. Below is a simplified table for selected grades:
Grade | C (%) | Mn (%) | P (%) (max) | S (%) (max) | Other Elements |
---|---|---|---|---|---|
B | 0.28 | 1.20 | 0.030 | 0.030 | – |
X42 | 0.28 | 1.30 | 0.030 | 0.030 | – |
X52 | 0.28 | 1.40 | 0.030 | 0.030 | – |
X60 | 0.28 | 1.40 | 0.030 | 0.030 | – |
X65 | 0.28 | 1.45 | 0.030 | 0.030 | – |
X70 | 0.28 | 1.65 | 0.030 | 0.030 | – |
- Carbon (C): Provides strength and hardness.
- Manganese (Mn): Improves strength and toughness.
- Phosphorus (P) and Sulfur (S): Kept to a minimum to avoid brittleness.
- Other Elements: May include elements like silicon (Si), nickel (Ni), chromium (Cr), molybdenum (Mo), and others, depending on the grade and additional requirements.
Mechanical Properties
The mechanical properties specified in API 5L ensure the pipes can withstand the conditions encountered in pipeline transportation systems.
Typical Mechanical Properties
Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Elongation (%) |
---|---|---|---|
B | ≥ 241 | 414-758 | ≥ 20 |
X42 | ≥ 290 | 414-758 | ≥ 20 |
X52 | ≥ 358 | 455-760 | ≥ 18 |
X60 | ≥ 414 | 517-758 | ≥ 17 |
X65 | ≥ 448 | 531-758 | ≥ 16 |
X70 | ≥ 483 | 565-758 | ≥ 15 |
- Yield Strength: The minimum stress at which material begins to deform plastically.
- Tensile Strength: The maximum stress that a material can withstand while being stretched before breaking.
- Elongation: Indicates the ductility of the material.
Manufacturing Process
- Seamless Pipe: Produced through processes like hot rolling, cold drawing, or extrusion.
- Welded Pipe: Manufactured by welding the seam; includes electric resistance welded (ERW), submerged arc welded (SAW), and other welding methods.
Heat Treatment
- Pipes may undergo heat treatment processes like normalizing, quenching and tempering, or stress relieving to achieve the desired mechanical properties.
Testing
API 5L specifies various tests to ensure the quality and performance of the pipes:
- Hydrostatic Testing: Ensures the pipe can withstand internal pressure without leaking.
- Nondestructive Testing (NDT): Includes ultrasonic testing, radiographic testing, and magnetic particle inspection to detect internal and surface defects.
- Mechanical Testing: Tensile tests, impact tests, and hardness tests
API 5L: Steel Pipes Specifications and Tolerances
API 5L specifies standards for seamless and welded steel pipes used in pipeline transportation systems in the petroleum and natural gas industries.
Specifications Range
- Outside Diameter: 2″ – 24″
- Wall Thickness: Schedule 10 through 160, STD, XS, XXS
Chemical Requirements
API 5L PSL1
Composition (%):
Composition | Seamless | Welded |
---|---|---|
Carbon (C) | 0.28 | 0.26 |
Manganese (Mn) | 1.20 | 1.35 |
Phosphorus (P) | 0.03 | 0.035 |
Sulfur (S) | 0.03 | 0.03 |
API 5L PSL2
Composition (%):
Composition | Seamless | Welded |
---|---|---|
Carbon (C) | 0.24 | 0.22 |
Manganese (Mn) | 1.20 | 1.20 |
Phosphorus (P) | 0.025 | 0.025 |
Sulfur (S) | 0.015 | 0.015 |
Silicon (Si) | 0.04 | 0.05 |
Vanadium (V) | 0.06 | 0.04 |
Niobium (Nb) | 0.05 | 0.05 |
Titanium (Ti) | 0.04 | 0.04 |
Mechanical Properties
API 5L PSL1
- Minimum Yield Strength: 35,500 PSI
- Minimum Tensile Strength: 60,200 PSI
API 5L PSL2
- Minimum Yield Strength: 35,000 – 65,300 PSI
- Minimum Tensile Strength: 60,200 – 110,200 PSI
Dimensional Tolerances
Outside Diameter (OD) Tolerance
API 5L PSL1
- Outside Diameter Range: 0.405″ – 84″
- OD Tolerance < 2.375″: 0.016″ – 0.063″ (Seamless & Welded)
- OD Tolerance 6.625″ – 24″: ±0.063″ (Seamless & Welded)
- OD Tolerance > 24″: ±0.079″ (Seamless), ±0.063″ (Welded)
API 5L PSL2
- Outside Diameter Range: 0.405″ – 84″
- OD Tolerance < 2.375″: 0.016″ – 0.063″ (Seamless & Welded)
- OD Tolerance 6.625″ – 24″: ±0.063″ (Seamless & Welded)
- OD Tolerance > 24″: ±0.079″ (Seamless), ±0.063″ (Welded)
Wall Thickness Tolerance
API 5L PSL1
- Wall Thickness Range: 0.068″ – 2.05″
- Wall Tolerance < 0.157″ (Seamless): 0.024″ – 0.02″
- Wall Tolerance 0.157″ – 0.984″ (Seamless): + (0.150 * wall thickness) – (0.125 * wall thickness)
- Wall Tolerance > 0.984″ (Seamless): +0.146″ – 0.120″
- Wall Tolerance < 0.197″ (Welded): ±0.02″
- Wall Tolerance 0.197″ – 0.591″ (Welded): ± (0.1 * wall thickness)
- Wall Tolerance > 0.591″ (Welded): ±0.06″
API 5L PSL2
- Wall Thickness Range: 0.068″ – 2.05″
- Wall Tolerance < 0.157″ (Seamless): 0.024″ – 0.02″
- Wall Tolerance 0.157″ – 0.984″ (Seamless): + (0.150 * wall thickness) – (0.125 * wall thickness)
- **Wall Tolerance >