As a leading Chinese manufacturer dedicated to excellence in steel pipe production, we supply a comprehensive range of materials that form the backbone of modern industry. Among these, L245M steel pipe stands out as a fundamental and versatile product, specified for countless onshore and offshore pipeline projects worldwide. This detailed guide explores L245M pipe, covering its specifications, properties, manufacturing, primary applications, and the compelling advantages of sourcing this critical material from our advanced facility.
1. Introduction to L245M / PSL2 Line Pipe
L245M is a designation under the internationally recognized API 5L (American Petroleum Institute Specification 5L) standard for seamless and welded steel line pipe. The “L” denotes “Line Pipe,” “245” indicates the minimum yield strength in Megapascals (MPa), and the “M” signifies that the pipe is supplied to the Manufacturing Procedure (PSL 2), which imposes stricter chemical, mechanical, and testing requirements compared to PSL 1.
Common Designations: API 5L L245M, ISO 3183 L245M, GB/T 9711 L245M. It is functionally equivalent to the older API 5L Grade B designation (PSL 2).
Material Type: It is a carbon-manganese (C-Mn) steel, optimized for strength, toughness, and excellent weldability, making it the workhorse grade for a vast array of pipeline systems.
2. Chemical Composition & Key Mechanical Properties
The controlled chemistry of L245M under PSL 2 ensures consistent performance, particularly enhanced toughness for demanding environments.
Typical Chemical Composition (% by weight, max unless range is given):
Carbon (C): ≤ 0.22% (lower carbon enhances weldability)
Manganese (Mn): ≤ 1.20%
Phosphorus (P): ≤ 0.025%
Sulfur (S): ≤ 0.015% (low sulfur improves ductility and through-thickness properties)
Silicon (Si): ≤ 0.45%
Additional Micro-alloying: Elements like Niobium (Nb), Vanadium (V), or Titanium (Ti) may be added in controlled amounts for grain refinement and strength enhancement, particularly in thermomechanically rolled (TMCP) plates for welded pipe.
Key Mechanical Properties (as per API 5L PSL 2):
Yield Strength (Min): 245 MPa (35,500 psi)
Tensile Strength (Range): 415 – 760 MPa (60,200 – 110,200 psi)
Yield-to-Tensile Ratio (Max): ≤ 0.93 (important for strain-based design applications)
Elongation: Minimum values specified based on sample size and grade.
Toughness Requirements (Mandatory for PSL 2): Pipe body and weld seam (if applicable) must meet minimum Charpy V-Notch impact energy absorption values, typically tested at 0°C (32°F) or lower as specified by the purchase order. This is a critical differentiator from PSL 1.
3. Our Manufacturing Processes for L245M Pipe
We produce high-quality L245M pipe through both seamless and welded manufacturing routes, selecting the optimal method based on diameter, wall thickness, and application requirements.
1. Seamless L245M Pipe Process (SMLS):
Raw Material: Round steel billets of specified chemistry.
Piercing & Rolling: The billet is heated and pierced to form a hollow shell, which is then elongated and sized through a series of rotary rolling mills (e.g., Mandrel Mill, Plug Mill).
Finishing: The pipe is cut to length, straightened, and subjected to heat treatment (normalizing if required) to achieve the desired mechanical properties and microstructure.
Advantages: No longitudinal weld seam, uniform wall thickness, excellent for high-pressure applications.
2. Welded L245M Pipe Process (ERW / SAW):
a) High-Frequency Electric Resistance Welding (HF-ERW):
Coiled steel strip (skelp) is unrolled, formed through a series of rolls into a cylindrical shape.
The open edges are heated by high-frequency current and forged together under pressure to create a solid-state weld.
The weld seam is heat-treated to normalize its microstructure.
b) Submerged Arc Welding (SAW):
Used for larger diameters. Steel plates are formed into a “J” or “U” shape, then welded internally and externally using an arc under a blanket of granular flux.
This process creates a robust, high-integrity weld with deep penetration.
4. Rigorous Quality Control and Testing (PSL 2 Compliance)
Our commitment to quality ensures every length of L245M pipe exceeds API 5L PSL 2 requirements:
Non-Destructive Testing (NDT):
Ultrasonic Testing (UT): 100% of the pipe body for laminar defects. The weld seam of welded pipe is 100% ultrasonically inspected.
Hydrostatic Testing: Each pipe section is tested to a pressure that induces a stress ≥ 95% of SMYS for a minimum of 5 seconds.
Eddy Current or Magnetic Particle Inspection: Often used on ERW seams for additional surface flaw detection.
Destructive Testing: Samples from each heat and pipe end are tested for tensile strength, elongation, and Charpy V-Notch impact toughness.
Dimensional & Visual Inspection: Strict checks on outside diameter, wall thickness, ovality, straightness, and surface condition.
Traceability & Certification: Each pipe is marked with heat number, size, grade, and manufacturer ID. A comprehensive Mill Test Certificate (MTC) per EN 10204 3.1/3.2 is provided, documenting all chemical and mechanical test results.
5. Primary Applications of L245M Steel Pipe
L245M is the cornerstone material for energy transportation and fluid conveyance:
Onshore Oil & Gas Gathering & Transmission Lines: For transporting crude oil, natural gas, and refined products over long distances.
Offshore Pipeline Systems: Used for subsea infield flow lines and some transmission lines, where its toughness is critical.
Water and Wastewater Pipelines: For major municipal and industrial water supply/discharge projects.
Structural and Piling Applications: Sometimes used in less critical structural roles or as foundation piles.
Industrial Piping: For plant utilities, slurry transport, and other general industrial services.
6. Key Advantages and Characteristics
Optimal Balance of Strength & Weldability: The controlled carbon equivalent (CE/Pcm) ensures excellent field weldability without requiring complex pre-heat procedures, reducing installation time and cost.
Guaranteed Low-Temperature Toughness: The mandatory PSL 2 Charpy impact requirements make it suitable for environments with low ambient temperatures or potential for dynamic stresses.
Cost-Effectiveness: As a lean C-Mn steel, it provides reliable performance at a competitive price point, offering exceptional value for large-scale pipeline projects.
High Dimensional Accuracy & Consistency: Our modern mills produce pipe with tight tolerances, facilitating easier and faster field alignment and welding.
Compatibility with Coatings: The clean, scale-free surface (achieved through shot blasting) provides an excellent substrate for external anti-corrosion coatings (FBE, 3LPE) and internal linings.
7. Corrosion Protection and End Finishing
To ensure long-term integrity in corrosive environments, we offer comprehensive finishing services:
External Coatings: Fusion-Bonded Epoxy (FBE), 3-Layer Polyethylene (3LPE), or 3-Layer Polypropylene (3LPP) applied to industry standards (e.g., ISO 21809, CSA Z245.20/21).
Internal Coatings: FBE or liquid epoxy linings to reduce friction and protect against product corrosion.
Bevelled Ends: Precision beveling to match standard welding specifications (e.g., ISO, ASME B16.25) for ready installation.
8. Comparison with Other Grades
vs. API 5L PSL 1 Grades (e.g., Gr B): L245M (PSL 2) offers stricter chemical control, mandatory toughness testing, and more comprehensive NDT, resulting in higher, more verifiable reliability for critical service.
vs. Higher Strength Grades (e.g., L360M/X52, L415M/X60): L245M provides ample strength for many medium-pressure applications, often with better weldability and lower cost. Grade selection depends on the specific design pressure and project economics.
9. Why Source L245M Pipe from Our Factory?
Uncompromising PSL 2 Compliance: We guarantee full adherence to API 5L and international equivalencies, with all supporting documentation.
Dual Manufacturing Capability: We provide both seamless and welded (HF-ERW & SAW) L245M pipe, offering unbiased recommendations for your application.
Integrated Coating & Logistics: We are a one-stop solution, providing coated, finished, and bundled pipes ready for shipment to global job sites via sea, rail, or land.
Project Expertise: Our technical team can assist with pipe specification, coating selection, and logistics planning for large-scale infrastructure projects.
Competitive Global Supply: Combining advanced manufacturing efficiency with direct factory pricing, we deliver outstanding value without compromising quality.
API 5L L245M steel pipe represents the dependable standard for constructing safe, efficient, and durable pipeline networks. Its proven balance of properties, governed by stringent PSL 2 requirements, makes it a trusted choice for engineers and developers worldwide. As a premier Chinese manufacturer–Tianjin xiangliyuan steel, we are committed to producing L245M pipe that not only meets but exceeds the expectations of the global energy and construction sectors.
For your next pipeline, piling, or industrial project, partner with a reliable supplier. Contact us–Tianjin xiangliyuan steel today for a detailed quotation, technical specifications, or to discuss your specific requirements for L245M pipe.
