Home > Welded Pipes > Oil & Gas Pipeline
Oil & gas pipelines operate under some of the most demanding service conditions in industrial environments. These pipelines must safely transport crude oil, refined hydrocarbons, natural gas, sour gas, multiphase fluids, and condensates over long distances, varied terrains, and fluctuating pressures. The pipelines must withstand internal pressure, external loads, corrosion, temperature variations, and transportation stresses during operation.
Welded pipes manufactured to API 5L (PSL1/PSL2), A671 (EFW), and A672 (EFW for moderate/high pressure) are widely used for cross-country transmission pipelines, refinery feeder lines, gas distribution networks, onshore pipeline grids, and in-plant hydrocarbon transfer lines.
These pipes ensure a balance of:
✔ high strength
✔ toughness
✔ weld integrity
✔ pressure containment
✔ dimensional accuracy
✔ corrosion control
making them essential for safe and reliable oil & gas flow.
Pipes carrying oil and natural gas face:
Therefore, the pipeline material must provide:
✔ high yield strength (API 5L Grade B to X80)
✔ fracture toughness
✔ controlled weld bead quality
✔ stable impact performance (CVN testing for PSL2)
✔ reliable EFW/SAW weld integrity
API 5L / A671 / A672 welded pipes are designed specifically to meet these requirements.
Oil & gas pipeline projects require long, continuous lengths with large diameters. Welded pipes offer:
Welded pipes (API 5L, A671, A672) deliver optimum performance for onshore pipeline networks transporting crude, natural gas, and refined hydrocarbons.
Oil & gas pipeline welded pipes are used in:
They play a crucial role across India, GCC, Africa, Europe, North America, and Southeast Asia.
These pipes support pipelines that must operate safely under fluctuating pressures, corrosive media, and extended distances.
| Pipeline Type | Typical Service Fluid | Recommended Standard | Purpose |
|---|---|---|---|
| Crude Oil Pipelines | Crude oil, heavy oil | API 5L (PSL1/PSL2) | Long-distance crude transmission |
| Natural Gas Pipelines | Natural gas, dry gas | API 5L PSL2 | High-pressure gas transmission |
| Sour Gas Lines (H₂S) | Sour gas | API 5L PSL2 (Sour Service) | HIC/SSC resistance |
| Refinery Feeder Lines | Crude feed, product feed | A671 / A672 | Continuous operation & pressure containment |
| Hydrocarbon Product Pipelines | Naphtha, diesel, kerosene | API 5L / A672 | Distribution & transport |
| City Gas Distribution Lines | PNG/CNG | API 5L | Medium-pressure urban distribution |
| Offsite Pipeline Networks | Refinery utility & product lines | A671 | Moderate pressure & high reliability |
| Plant Piping & In-Plant Transfer | Hydrocarbons, condensate | A53 / API 5L | General oil & gas plant distribution |
| Application Parameter | API 5L Line Pipe | A671 EFW Pipe | A672 EFW Pipe |
|---|---|---|---|
| Primary Application | Cross-country crude & gas pipelines | Refinery & petrochemical pipelines | High-pressure hydrocarbon pipelines |
| Pipeline Type | Transmission & distribution | Process & interconnection lines | Critical high-pressure service |
| Pipeline Location | Onshore • Offshore • Subsea | Above-ground & underground | Above-ground & underground |
| Service Fluids | Crude Oil, Natural Gas, LNG, LPG, Petroleum Products | Hydrocarbons, Steam, Condensate | High-pressure Hydrocarbons, Gas, Steam |
| Pipeline Operating Pressure | Medium to High | High | Very High |
| Pipeline Temperature Range | –46°C to +250°C | –20°C to +400°C | –20°C to +450°C |
| Construction Method | Stringing + Field Welding + Coating | Plant Piping + Field Joint Welding | Critical pipeline sections |
| Recommended Coating Systems | 3LPE, 3LPP, FBE Internal/External | 3LPE, 3LPP, FBE | 3LPE, 3LPP, FBE |
| Typical Installation Areas | Cross-country pipelines, coastal pipelines, offshore rigs | Refineries, petrochemical complexes | High-pressure refinery loops, compressor stations |
| Strength Requirement (PSL) | PSL1 / PSL2 Mandatory | 3.1 / 3.2 Certified | 3.1 / 3.2 Certified |
| Weld Integrity Requirement | 100% UT / RT mandatory | 100% UT / RT | 100% UT / RT (High Class) |
| Industry Compliance | API, ANSI, ISO, NACE | ASTM, ASME | ASTM, ASME |
| Major Users | Oil & Gas Companies, EPC Contractors, Pipeline Builders | Refineries, Chemical Plants | Refineries, Petrochemical Plants |
Cross-Country Crude Oil Pipelines — API 5L Welded Pipes
Used for transporting crude from production fields to refineries.
Pipes must handle:
API 5L PSL2 welded pipes (Grades X42–X70) deliver required toughness & strength.
Natural Gas Transmission Lines — API 5L PSL2
These pipelines operate at high pressure and require:
SAW welded pipes in PSL2 grade maintain safe gas transmission.
Sour Gas Pipelines (H₂S Service)
Sour service demands resistance to:
PSL2 Sour Service grades ensure reliable transport.
Refinery Feeder & Transfer Lines — A671 / A672
Used to transport crude oil, heater feed, intermediate hydrocarbons, and refined products within refineries.
A671/A672 EFW welded pipes offer:
Hydrocarbon Product Pipelines
Transporting refined products such as diesel, petrol, naphtha, LPG.
API 5L / A672 pipes ensure safe movement across distances.
City Gas Distribution Lines
Medium-pressure pipelines supplying PNG & CNG within cities.
API 5L ERW/SAW welded pipes provide cost-effective reliability.
Offsite & Utility Pipelines (Refinery Complexes)
Includes firewater mains, product lines, return lines.
A671 provides good strength & durability.
In-Plant Piping
For condensate, hydrocarbons, and product distribution.
API 5L/A53 welded pipes commonly used.
| Industry | Pipeline Application |
|---|---|
| Oil Production | Crude gathering pipelines |
| Gas Production | High-pressure gas lines |
| Refineries | Crude & product feed pipelines |
| Petrochemicals | Hydrocarbon distribution |
| Midstream Operators | Cross-country pipelines |
| City Gas Distribution | Medium-pressure networks |
Looking for API 5L / A671 / A672 welded pipes for oil & gas pipelines?
✔ Cross-country pipeline supply
✔ Sour service grades
✔ PSL2 quality
✔ Coated & non-coated options
52-A, Mulji Thackersi Bldg, Islampura Street, Shop No. 10, Near Alankar Cinema, Mumbai – 400 004
alloy@inoxsteelindia.in, steel@inoxsteelindia.in
+91 9930796690
Yes. PSL2 ensures impact toughness, weld integrity, and fracture resistance.
3LPE, FBE, Coal Tar, and Bitumen coatings.
Yes, they are suitable for moderate/high pressure hydrocarbon piping.
Grades X42, X46, X52, X60, X65, X70.
Applications of welded pipes in crude oil pipelines, gas transmission, refinery feeder lines, and hydrocarbon distribution networks.