API 5L X70 pipe

API 5L X70 pipe is a high-strength conduit manufactured in accordance with the American Petroleum Institute (API) 5L specification for Steel pipes for Pipeline transportation, where "X70" indicates its minimum yield strength of  70 ksi (approximately  485 MPa). This pipe material is available in two quality grades: PSL 1 (basic grade) and PSL 2 (enhanced grade). It can be produced into seamless pipes as well as various welded pipes (ERW, LSAW, SSAW/HSAW), and is widely used in high-pressure, long-distance oil and gas transportation and pipeline projects in sulfur-resistant environments.

API 5L X70 Chemical Composition

API 5L X70 PSL 1 Chemical Composition

API 5L X70 PSL 2 Chemical Composition

Mechanical properties

Minimum yield strength (Rt0.5) : 70 300 psi (≈485 MPa); Minimum tensile strength (Rm) : 82 700 psi (≈570 MPa); Elongation (2 in Af) ≥ 17% (the weld seam and the pipe body require the same minimum tensile strength to ensure welding performance).

Manufacturing process

Seamless steel pipe (SMLS) : Suitable for small-diameter and high-pressure applications, ensuring the integrity of the entire pipe body.
Welded pipes: including various processes such as ERW, LSAW, and SSAW, are suitable for scenarios with large diameters and high economic requirements.
Heat treatment technology: PSL  grade 2 tubes are often treated with TMCP (thermal mechanical control process) or Q&T (quenching + tempering) to achieve better mechanical properties.

Dimensions and specifications: Nominal diameter (NPS) : ½ "to 24" (12.7 mm to 610 mm); Wall thickness specifications (Schedule) : Sch 10 - Sch 160, as well as STD, XS, XXS; For large-diameter welded pipes, the diameter can reach 48 "(1219 mm).

Inspection and Testing of API 5L X70 pipe

Hydrostatic test: All pipes must undergo an internal pressure test to verify their sealing performance and strength.
Non-destructive testing (RT/UT/MT, etc.) : PSL 2 adds comprehensive flaw detection requirements for welds and pipe bodies.
Impact toughness test: Charpy V-Notch test ensures that the pipe material still has sufficient toughness in a low-temperature environment.

Application field
API 5L X70 high-strength and high-toughness pipes are widely used in:

Long-distance oil and gas pipelines.
Urban gas and industrial gas transportation.
Offshore platform pipeline system.
High-pressure pipelines for chemical, petrochemical and power projects.
It can also be used in other engineering scenarios that require a balance between high pressure, corrosion resistance and welding reliability.

Summary
API 5L X70 pipe (also known as L485) is a high-end API 5L pipe steel with:

Yield strength ≥ 485 MPa and good tensile strength;
Excellent toughness and welding performance;
Customizable level (PSL1/2/Sour Service);
A complete testing system ensures safe and reliable application.
It performs exceptionally well in long-distance oil and gas transportation, high-pressure and corrosive environments, and enjoys extremely high engineering reliability.

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