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Help CenterSteel Pipe & Tube & Petroleum Steel Pipe，L245（B）、L290（X42）、L360（X52）、L415（X60）、L485（X70）、L245NS、L360QS、L485QS、E75（25CrMn）、X95、G105、S135
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Steel Pipe & Tube & Petroleum Steel Pipe，L245（B）、L290（X42）、L360（X52）、L415（X60）、L485（X70）、L245NS、L360QS、L485QS、E75（25CrMn）、X95、G105、S135NegotiableMOQ: 5 Metric Tons -
Steel Pipe & Tube & Petroleum Steel Pipe，L245（B）、L290（X42）、L360（X52）、L415（X60）、L485（X70）、L245NS、L360QS、L485QS、E75（25CrMn）、X95、G105、S135NegotiableMOQ: 5 Metric Tons
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Steel Pipe & Tube & Petroleum Steel Pipe，L245（B）、L290（X42）、L360（X52）、L415（X60）、L485（X70）、L245NS、L360QS、L485QS、E75（25CrMn）、X95、G105、S135NegotiableMOQ: 5 Metric Tons
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Steel Pipe & Tube & Petroleum Steel Pipe，L245（B）、L290（X42）、L360（X52）、L415（X60）、L485（X70）、L245NS、L360QS、L485QS、E75（25CrMn）、X95、G105、S135NegotiableMOQ: 5 Metric Tons
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Steel Pipe & Tube & Petroleum Steel Pipe，L245（B）、L290（X42）、L360（X52）、L415（X60）、L485（X70）、L245NS、L360QS、L485QS、E75（25CrMn）、X95、G105、S135NegotiableMOQ: 5 Metric Tons
Petroleum pipes (OCTG) are special core pipes for the exploration, production, transportation and refining of oil and natural gas. They are mainly divided into four categories: Casing, Tubing, Drill Pipe and Line Pipe. Manufactured in compliance with API and national standards, the products feature high strength, high toughness, high pressure resistance and excellent corrosion resistance. Below is a detailed introduction covering classification, standards, materials, specifications, performance, threads, manufacturing, application, packaging and delivery schedule.
1. Product Classification & Main Applications
1.1 Casing
It is run into the wellbore to support the well wall, isolate formations and prevent well collapse and interlayer fluid channeling, serving as the "skeleton" of an oil well.Main types: Surface Casing, Intermediate Casing, Production Casing and Liner.
1.2 Tubing
Suspended inside the casing, it acts as the passage for oil and gas lifting, water injection, polymer injection, acidizing and fracturing.Common specifications: Outer diameter 60.3–114.3 mm, wall thickness 4.83–9.52 mm, length 6–12.5 m.
1.3 Drill Pipe
It transmits torque and drilling pressure, and delivers drilling fluid, connecting the drill bit and surface equipment.Structure: Pipe body + Tool Joint. Common steel grades: E75, X95, G105, S135.
1.4 Line Pipe
Used for long-distance transportation of crude oil, natural gas and refined oil products, including main pipelines and gathering pipelines.Production processes: Seamless pipe (small diameter), Longitudinal Submerged Arc Welded pipe (large diameter).
2. Executive Standards
2.1 International Standards (API)
API 5CT: Casing and Tubing (Primary standard)
API 5D: Drill Pipe
API 5L: Line Pipe (PSL1 / PSL2)
API 5B: Thread processing, measurement and inspection
2.2 Chinese National Standards
GB/T 9711: Line Pipe (Equivalent to API 5L)
GB 9948: Petroleum Cracking Pipe (Furnace pipe, heat exchanger pipe)
SY/T 6194: Technical delivery conditions for casing and tubing
3. Materials & Steel Grades (Mechanical & Corrosion Resistance)
3.1 Steel Grades for Casing & Tubing (API 5CT)
J55 / K55: Low strength grade, for shallow wells, low pressure and non-corrosive environments.
N80: Medium and high strength grade, widely used in medium-deep conventional wells. N80-1 (Normalized & Tempered); N80-Q (Quenched & Tempered) with higher collapse resistance.
L80: Good resistance to CO₂ corrosion, applicable to medium-deep wells and mildly corrosive conditions.
C90 / T95: Resistant to H₂S stress cracking, designed for sulfur-containing wells.
P110: Ultra-high strength grade, suitable for deep wells, ultra-deep wells and high-pressure wells.
13Cr / Super 13Cr: Excellent CO₂ corrosion resistance, for high-temperature and heavily corrosive wells.
Nickel-based Alloy: Applied in extreme corrosive environments with high chloride ion, H₂S and CO₂ content.
3.2 Steel Grades for Line Pipe (API 5L / GB/T 9711)
PSL1: L245 (B), L290 (X42), L360 (X52), L415 (X60), L485 (X70)
PSL2: L245NS, L360QS, L485QS (Good low-temperature toughness and H₂S resistance)
3.3 Steel Grades for Drill Pipe
E75 (25CrMn), X95, G105, S135 (High-strength alloy steel)
4. Dimension Specifications (Outer Diameter × Wall Thickness × Length)
4.1 Casing
Outer diameter: 114.3–508 mm (4.5–20 inch)
Wall thickness: 6.35–12.7 mm
Length range: R1 (4.8–7.3 m), R2 (7.3–10.7 m), R3 (10.7–12.2 m)
4.2 Tubing
Outer diameter: 60.3 mm (2 3/8 in), 73 mm (2 7/8 in), 88.9 mm (3 1/2 in), 114.3 mm (4 1/2 in)
Wall thickness: 4.83–9.52 mm
Length: 6–12.5 m (9 m fixed length is commonly used)
4.3 Line Pipe
Outer diameter: 21.3–1067 mm (1/8–42 inch)
Wall thickness: 2–50 mm (up to 100 mm for high-pressure service)
5. Mechanical Properties (Core Indexes of API 5CT)
Yield Strength: J55 ≥ 379 MPa; N80 ≥ 552 MPa; P110 ≥ 758 MPa
Tensile Strength: J55 ≥ 517 MPa; N80 ≥ 689 MPa; P110 ≥ 862 MPa
Elongation: ≥ 12% (Gauge length: 50 mm)
Impact Toughness: ≥ 27 J (V-notch, 0℃)
Collapse Resistance: N80-Q outperforms N80-1, a key index for deep well service
6. Thread Types (Connection & Sealing Performance)
6.1 API Standard Threads
Tubing Round Thread (TBG): General sealing performance, mainly for shallow wells.
Casing Short Round Thread (SC): Medium connection strength.
Casing Long Round Thread (LC): High connection strength, suitable for medium-deep wells.
Buttress Thread (BTC): Large bearing surface and excellent anti-slip capacity, ideal for deep wells and high-pressure wells.
6.2 Premium Connection Threads
Features: Metal-to-metal sealing, high torque resistance, superior gas tightness and corrosion resistance.Common types: VAM TOP, BGT1, BGC, Hydril CS (For premium wells, sulfur-containing wells and high-pressure gas wells)
7. Manufacturing Process
Seamless Pipe: Billet heating → Piercing → Pipe rolling → Sizing → Straightening → Heat treatment (Normalizing / Quenching & Tempering) → Thread machining → Non-destructive testing → Marking
Welded Pipe: Steel coil forming → Welding (ERW / LSAW) → Heat treatment → Thread machining → Non-destructive testing → Marking
Heat Treatment: N80-Q and P110 adopt quenching and high-temperature tempering to balance strength and toughness; L80 adopts normalizing and tempering for enhanced CO₂ corrosion resistance.
Non-destructive Testing: 100% inspection by Ultrasonic Testing (UT), Eddy Current Testing (ET), Magnetic Particle Testing (MT) and Hydrostatic Pressure Test.
8. Application & Selection Guidelines
Shallow Wells (Depth ＜ 2000 m): J55/K55 casing + N80 tubing with round thread, cost-effective solution.
Medium-deep Wells (2000–4000 m): N80-Q / L80 casing + P110 tubing with BTC thread, for high collapse resistance and corrosion resistance.
Deep Wells (Depth ＞ 4000 m): P110 / Super 13Cr casing with premium thread, featuring high collapse resistance and gas tightness.
Sulfur-containing Wells (H₂S): C90 / T95 / Sulfur-resistant L80 grade, to prevent H₂S induced stress cracking.
Long-distance Transmission Pipelines: X70 / X80 (L485 / L555) PSL2 grade, with good low-temperature toughness and H₂S resistance.
9. Surface Treatment & Packaging
Surface Treatment: Anti-rust paint on outer surface; anti-corrosion coating on inner surface to reduce scaling and corrosion; thread coated with anti-rust grease and fitted with thread protectors.
Packaging: Bundled (5–10 pieces per bundle), both ends equipped with thread protectors, wrapped with moisture-proof film and steel strips, suitable for sea and land transportation.
10. Delivery Schedule & Technical Support
Standard specifications: Shipment from Tianjin Port, delivery within 5–7 working days.
Special materials and custom threads: Delivery within 15–20 working days.
Technical support: Provide API 5CT / 5L certificates, material test reports, NDT reports and thread inspection reports. Third-party inspection by SGS, BV and other institutions is acceptable.
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