Products Features

High strength matched with excellent toughness (core advantage)

The core advantage of API 5L X70 lies in its excellent balance between high strength and superior toughness. Thanks to its ultra-low carbon micro-alloyed design (carbon content typically ≤ 0.08-0.10%) and TMCP controlled rolling and cooling process, X70 maintains a minimum yield strength of 485 MPa and a minimum tensile strength of 565 MPa while still offering excellent low-temperature impact toughness (-30°C impact energy ≥ 50 J). Its yield strength is approximately 1.67 times that of X42 (290 MPa), making it suitable for high-pressure transmission applications with higher pressures and larger wall thicknesses.

Performance indicators	PSL1 Requirements	PSL2 Requirements
Minimum Yield Strength (MPa)	485	485
Maximum Yield Strength (MPa)	-	605
Minimum Tensile Strength (MPa)	565	565
Maximum Tensile Strength (MPa)	-	760
Yield ratio	-	Usually ≤ 0.93
Elongation	≥ 19-21%	≥ 19-21%

Note: PSL2 imposes limits on both maximum yield strength and maximum tensile strength (with upper limits of 605 MPa and 760 MPa respectively), ensuring the material has sufficient plastic deformation capability and a higher safety margin to avoid brittle failure risks caused by an excessively high yield-to-tensile ratio.

Excellent welding performance (core requirement for pipeline steel)

The ultra-low carbon equivalent design of API 5L X70 ensures excellent welding performance, which is a core requirement for large-scale construction of pipeline steels. The PSL2 grade requires a carbon equivalent (CEIIW) ≤ 0.43 and Pcm ≤ 0.25, ensuring good toughness and resistance to cold cracking in the heat-affected zone under field welding conditions.
Key Welding Points:
• Low CE value:
Effectively reduces the tendency of the welding heat-affected zone to harden and lowers the risk of cold cracks
• Low-harmful-element content:
The content of P and S is strictly controlled (S ≤ 0.010%) to ensure the purity of the weld and base metal

• Suitable for various welding methods:
butt welding of seamless steel pipes, submerged arc welding of spiral/straight seam welded pipes, etc., with good field ring welding performance

For PSL1 grade, the upper limit of carbon content is relatively wide (≤ 0.24%), and preheating at 100-150°C is recommended during welding; for PSL2 grade, the carbon content requirement is stricter (≤ 0.08-0.10%), resulting in better weldability and typically no need for special preheating or only requiring a lower preheating temperature.

Excellent low-temperature toughness and resistance to brittle fracture

The API 5L X70 PSL2 grade requires Charpy V-notch impact testing to ensure the material's resistance to brittle fracture under low-temperature service conditions. The fine-grained microstructure obtained through the TMCP process (with a grain size typically ≥ 10) significantly enhances the material's low-temperature toughness, enabling X70 line pipe steel to be reliably applied in cold regions and environments with large seasonal temperature variations.
Typical impact toughness index (PSL2):
• Test temperature: Typically -30°C or lower (as per user requirements)
• Minimum impact energy:≥ 50 J (average value) / ≥ 35 J (single value)

Good corrosion resistance and environmental adaptability

API 5L X70 exhibits good resistance to uniform corrosion in normal atmospheric, fresh water, soil, and oil and gas media. For acidic service environments (containing H₂S), API 5L PSL2 Appendix J provides supplementary requirements for acid-resistant pipes (X70MS / L485MS), including lower sulfur content (≤ 0.002%), hardness control (≤ 250 HV), and strict verification of HIC/SSC resistance performance.

For the marine environment, Appendix H and Appendix J of PSL2 provide corresponding material supplementary requirements applicable to offshore platform structural pipes and subsea pipelines.

Good cold bending and processing performance

API 5L X70 has a lower carbon content and a moderate yield-to-tensile ratio (typically ≤ 0.93 for PSL2), which gives it good cold bending formability. It is suitable for cold-bent pipe production and can be used to manufacture hot-bent elbows through hot bending processes. It also exhibits good shearing, blanking, and roll forming properties in coil and plate conditions. Its work hardening characteristics help improve strength after cold bending.

Technical Specifications

Chemical Composition(API Spec 5L / ISO 3183)

Element	PSL1 Seamless Tube	PSL1 Welded Pipe	PSL2	Note
C	≤ 0.24%	≤ 0.24%	≤ 0.08-0.10%	Low-carbon design to ensure weldability and low-temperature toughness
Mn	≤ 1.40%	≤ 1.40%	≤ 1.70%	Solid solution strengthening, improve strength
P	≤ 0.030%	≤ 0.030%	≤ 0.025%	Harmful elements, strictly controlled
S	≤ 0.030%	≤ 0.030%	≤ 0.010%	Harmful elements, strictly controlled to ensure low-temperature toughness
Si	≤ 0.45%	≤ 0.45%	≤ 0.50%	Deoxidizer, improve strength
V	≤ 0.05%	≤ 0.05%	≤ 0.10%	Microalloying elements, precipitation strengthening
Nb	≤ 0.05%	≤ 0.05%	≤ 0.06-0.08%	Microalloying elements, controlled rolling for fine grain
Ti	≤ 0.04%	≤ 0.04%	≤ 0.02-0.04%	Microalloying elements, precipitation strengthening
Cr	-	-	≤ 0.50%	Improve hardenability and corrosion resistance
Mo	-	-	≤ 0.20%	Improve hardenability and temper stability
Ni	-	-	≤ 0.30%	Improve low-temperature toughness
Cu	-	-	≤ 0.20%	Improve atmospheric corrosion resistance
CEIIW	-	-	≤ 0.43%	Carbon equivalent, controlling weldability
Pcm	-	-	≤ 0.25%	Crack Sensitivity Index
Fe	Remaining quantity(≈ 97%)	Remaining quantity(≈ 97%)	Remaining quantity(≈ 97%)	Matrix element

Physical Properties

Property	Value/Range	Test Conditions
Density	≈ 7.85 g/cm³	Room Temperature (20°C)
Melting Point	≈ 1420-1460°C	---
Elastic modulus	≈ 207 GPa	Room Temperature
Thermal Conductivity	≈ 50 W/(m·K)	Room Temperature
Coefficient of Thermal Expansion (20-100°C)	≈ 11.5 × 10⁻⁶ /K	---
Poisson's ratio	≈ 0.28	Room Temperature

Mechanical Properties (Typical Value)

Performance	PSL1	PSL2	Implementation standards
Minimum Yield Strength	485 MPa	485 MPa	API Spec 5L / ISO 3183
Maximum Yield Strength	-	605 MPa	API Spec 5L / ISO 3183
Minimum Tensile Strength	565 MPa	565 MPa	API Spec 5L / ISO 3183
Maximum Tensile Strength	-	760 MPa	API Spec 5L / ISO 3183
Elongation	≥ 20%	≥ 20%	API Spec 5L

Note: The 'X70' in API 5L X70 indicates the minimum yield strength of 70,000 psi (approximately 485 MPa), with the number representing the unit of kilopounds per square inch (ksi). The actual yield strength of the pipe material typically ranges from 500 to 565 MPa, and the tensile strength ranges from 580 to 650 MPa.

Applicable Media

1. Natural gas, crude oil, and refined oil: High-pressure long-distance main transmission lines

2. Water and slurries: Long-distance water pipelines, slurry transportation

3. Chemical media: High-pressure fluid pipelines in chemical plants

4. Urban gas: Urban high-pressure gas distribution networks

5. Structural pipes: Building structures, offshore platform jackets (non-corrosive environments)

6. General corrosive environments: Conventional soil, atmosphere, freshwater

Note: API 5L X70 is not suitable for high-temperature, high-pressure, strongly acidic media (such as hot concentrated hydrochloric acid and hydrofluoric acid). In acidic oil and gas environments containing H₂S, special grade materials specified in Appendix J of API 5L PSL2 (acid-resistant pipes X70MS / L485MS) should be selected, with additional control over sulfur content (≤ 0.002%), hardness (≤ 250 HV), and HIC resistance performance.

Product Form and Manufacturing Process

Seamless steel pipe (Seamless)

Process: Hot Rolling Piercing + Extension Rolling

Diameter Range: 21.3 - 1067 mm (1/2" - 42")

Wall thickness range: 2 - 150 mm

Features: Seamless, high pressure-bearing capacity, suitable for high-pressure oil and gas mainlines

Typical applications: high-pressure fluid transportation, oil and gas wellhead gathering and transmission pipelines

Straight Seam High-Frequency Resistance Welded Pipe (ERW)

Process: Hot-rolled coil → Cold bending forming → High-frequency resistance welding

Outer Diameter Range: Typically ≤ 610 mm (24")

Wall thickness range: Typically ≤ 20 mm

Features: High dimensional accuracy, high production efficiency, and significant cost advantages

Typical applications: medium and low-pressure oil and gas branch lines, urban gas pipelines, and structural pipes

Welding Heat Input Control: High-frequency welding at ≥ 100 kHz (PSL2 requirement) to ensure stable weld quality

Spiral Submerged Arc Welded Pipe (SSAW)

Process: Hot-rolled coil → Spiral forming → Dual-sided submerged arc welding

Outer Diameter Range: Typically 219 - 2500 mm

Wall thickness range: 6 - 25 mm

Features: The large diameter offers significant advantages, allowing steel strips of the same width to produce various diameters. The stress of spiral welds is only 75-90% of that of straight seams, enabling them to withstand higher pressures. Theoretically, they can be continuously produced in unlimited lengths.

Typical applications: large-diameter water/gas transmission pipelines, offshore engineering jacket

Straight Seam Submerged Arc Welded Pipe (LSAW)

Process: Steel Plate → JCOE Forming / UOE Forming → Dual-Sided Submerged Arc Welding

Outer Diameter Range: 406 - 1620 mm (16" - 64")

Wall thickness range: 6 - 50 mm

Features: Short welds, low welding material consumption, wide range of outer diameter and wall thickness

Typical applications: high-pressure long-distance transmission pipelines, submarine pipelines, oil and gas gathering and transportation mainlines

Applicable Standards and Delivery Condition

Standard:API Spec 5L,ISO 3183,GB/T 9711

Product Specification Level: PSL1 (Basic Level), PSL2 (Enhanced Level)

Delivery Condition: Hot-rolled, Controlled Rolling (TMCP), Normalized, Normalized Rolling, Heat Treatment (Quenching + Tempering), etc.

End Processing: Flat Ends, Beveled Ends, Threaded Ends, Special Fitting Ends

Certificate: When complying with PSL2 requirements, a compliance certificate (SR15.1 mandatory) must be provided, and full-process traceability must be implemented (SR15.2 mandatory).

Treatment Regime and Welding Key Points

The final performance of API 5L X70 depends on the TMCP controlled rolling and controlled cooling process:

1. Controlled Rolling and Controlled Cooling (TMCP, used to obtain a fine-grained microstructure and optimal mechanical properties):

Heat to 1100-1200°C for rough rolling, then perform controlled rolling with large reduction in the 850-950°C finishing temperature range (rolling in the non-recrystallization zone), followed by controlled cooling within 600-800°C. This results in a uniform and fine acicular ferrite + bainite microstructure (grain size typically ≥ 10), ensuring a balanced combination of strength and toughness. For sour service line pipes, TMCP is the preferred process route to avoid the precipitation of harmful phases.

2. Post-weld Heat Treatment (if required):

If stress relief is required after pipe ring weld welding, post-weld heat treatment at 550-650°C for 1-2 hours can be performed. Post-weld heat treatment should pay attention to controlling the heating and cooling rates to avoid affecting the microstructure and properties of the base material.

Important Reminder:

In conventional oil and gas transmission environments without H₂S, stress relief heat treatment is typically not required after welding.

For pipelines in an acidic environment (containing H₂S), strict compliance with Appendix J of API 5L PSL2 is required to prevent excessive hardness (≤ 250 HV) caused by improper post-weld heat treatment.

During welding, strict control of heat input (recommended 0.5-2.5 kJ/mm) and interpass temperature (typically ≤ 100°C) is required to prevent grain coarsening in the heat-affected zone and excessive hardness.

API 5L X70 (L485) is suitable for high-pressure oil and gas long-distance transmission pipelines, marine pipelines, and high-strength structural pipe applications. It is recommended for use in the following areas:

Application Fields

Long-distance main transmission lines for oil and natural gas
● High-pressure long-distance oil and gas transmission main pipelines (national projects such as West-to-East Gas Transmission)
● Submarine pipelines, marine risers
● Main gathering and transmission lines for large gas fields, main natural gas pipeline networks
Urban high-pressure gas pipeline network
● Urban high-pressure gas transmission and distribution main pipeline network
● Inlet and outlet main pipelines of urban gas high-pressure pressure regulation stations
Water Conveyance and Irrigation Engineering
● Long-Distance High-Pressure Water Transmission Main Pipeline
● Accompanying Pipelines for Large-Scale Water Conservancy Projects
Chemical Engineering and Industrial High-Pressure Piping
● High-pressure process pipelines in chemical industrial parks
● Power station high-pressure circulating water pipe
Structural Tubing (High Strength)
● Jacket for offshore platform (high-strength section)
● Pipes for pile foundations of large bridges
● Steel structural support pipes for high-rise buildings
● Structural pipes for offshore wind power foundations

Delivery and Customization

We offer flexible and reliable supply chain solutions to ensure you receive API 5L X70 line pipe that perfectly matches your project requirements.

Form	Seamless Steel Pipe	Straight Seam Resistance Welded Pipe (ERW)	Spiral Submerged Arc Welded Pipe (SSAW)	Straight Seam Submerged Arc Welded Pipe (LSAW)
Conventional Range	Outer Diameter: 21.3 - 1067 mm; Wall Thickness: 2 - 150 mm	Outer Diameter: 21.3 - 610 mm; Wall Thickness: 2 - 20 mm	Outer Diameter: 219 - 2500 mm; Wall Thickness: 6 - 25 mm	Outer Diameter: 406 - 1620 mm; Wall Thickness: 6 - 50 mm
Customization Capability	Hot-rolled seamless pipes, fixed-length cutting, bevel machining, pipe end threads, special heat treatment conditions	High-frequency straight-seam welded pipes, fixed-length cutting, bevel processing, galvanization/plastic coating treatment	Large-diameter spiral welded pipes, fixed-length cutting, bevel processing, anti-corrosion coating (FBE/3PE)	JCOE/UOE forming, length cutting, bevel machining, special pipe end treatment

Why Choose Us? - Reliable Engineering Technology. Dependable Delivery.

We are not just a supplier, but a trusted materials partner for you in China.

Vertically Integrated Production

Own 20,000㎡ facility with 10+ automated lines (8,000+ tons/year). In-house tooling & die center enables rapid customization and effective cost control - no middleman markup.

Strict Quality Control at Every Stage

Full traceability across key QC checkpoints throughout production. 100% compliant with ASTM/ASME, EN, and GB standards. Material test reports available with every shipment.

Reliable Delivery & Export Packaging

10+ years exporting to Europe, North America, Southeast Asia & Middle East with waterproof and anti-rust protection, combined with flexible shipping options ensures safe and on-time arrival.

Sample Validation Before Mass Production

We provide free samples for quality verification, allowing you to place bulk orders only after approval. We ensure consistency from sample to mass production by accurate dimensional measurement and transparent manufacturing.

FAQ

Q: What are the main advantages of API 5L X70?

Q: What is the difference between API 5L X70 PSL1 and PSL2? How to choose between them?

Q: What are the differences between API 5L X42, X52, X60, X65, and X70? How to choose among them?

Q: What is the maximum operating temperature for API 5L X70?

Q: What is the welding performance of API 5L X70?

Q: What is the corrosion resistance of API 5L X70?

Q: Can API 5L X70 replace ASTM A53 or X52/X60?

It can partially replace, especially in applications with high intensity and good weldability requirements:
Scenarios suitable for substitution:
• Ultra-high-pressure fluid transportation:
The strength of X70 (485 MPa) is significantly higher than that of A53 B (240 MPa), X42 (290 MPa), X52 (360 MPa), and X60 (415 MPa). Under the same outer diameter and pressure, it allows for a substantial reduction in wall thickness, resulting in significant weight savings.
• Main trunk line of long-distance pipelines:
X70 is the main steel grade for high-pressure long-distance pipeline transportation. It features high strength and good cost-effectiveness, and has been widely adopted in national projects such as the West-East Gas Transmission Project.

• Marine engineering structural pipes:
The high-strength properties of X70 are suitable for heavy-load structures such as offshore platforms

Scenarios where substitution is not suitable:
• Non-pressure components:
A53/A500 structural tubes are more cost-effective
• Medium and low-pressure pipelines:
X42 or X52 are sufficient, X70 has excessive strength
• Acidic environment (H₂S):
It is necessary to confirm that the anti-acid requirements are met. Ordinary X70 is not applicable; X70MS should be selected instead.
Material Selection Recommendations:
For specific material selection, please provide detailed operating conditions (design pressure, conveyed medium, ambient temperature, presence of H₂S/CO₂, welding requirements, pipe diameter and wall thickness). We can assist with a technical and economic comparison analysis to help you make the optimal choice between X70 and other steel grades.
For quotations on specific specifications, material test reports, or technical parameter sheets, please contact our sales engineers. We support customizing dimensions, delivery conditions, and surface treatments (coating/plating) as per requirements, and provide a full set of international certification documents (API, ISO, EN, GB, etc.).

Hot Tags: api 5l x70, China api 5l x70 manufacturers, suppliers, factory

Comparison Item	PSL1(Basic Level)	PSL2 (Enhanced Level)
Carbon Content Upper Limit (Welded Pipe)	≤ 0.24%	≤ 0.08-0.10%
Sulfur Content Upper Limit (Seamless Pipe)	≤ 0.030%	≤ 0.010% (stricter for PSL2)
Carbon Equivalent (CEIIW)	No requirements	≤ 0.43% (stricter welding control)
Maximum Yield Strength	No upper limit	≤ 605 MPa (Ensure ductility and avoid excessively high yield-to-tensile strength ratio)
Maximum Tensile Strength	No upper limit	≤ 760 MPa
Impact toughness	Only required when specified by the user	Mandatory Requirement (-30°C, Low Temperature Toughness Guarantee)
Non-destructive testing	Non-compulsory	Mandatory requirement
Traceability	Only traceable after passing detection (when specified by the user)	Mandatory full-process traceability(SR15.2 mandatory)
Certificate Requirements	Provide only when specified by the user	Mandatory provision of compliance certificates(SR15.1 mandatory)
Selection suggestions	Primarily used for general pipelines and common corrosive environments	Primarily used for high-pressure, low-temperature, acidic environments and critical projects

Comparison Item	X42	X52	X60	X65	X70
Minimum Yield Strength (MPa)	290 (42 ksi)	360 (52 ksi)	415 (60 ksi)	450 (65 ksi)	485 (70 ksi)
Minimum Tensile Strength (MPa)	414 (60 ksi)	460 (67 ksi)	520 (75 ksi)	535 (75 ksi)	565 (82 ksi)
Strength grade	Moderately low	Medium	Moderately high	Moderately high	High
Wall Thickness and Cost	Thicker and lower cost	Moderate, good value for money	Thin and of moderate cost	Thin and of moderate cost	Thinnest, high material cost
Weldability	Excellent	Excellent	Good	Good	Better (with a slightly higher CE value)
Typical applications	Medium and low pressure pipeline networks, structural pipes	Medium and high-pressure long-distance transmission pipelines (main force)	High-pressure main transmission lines	High-pressure main transmission lines	ltra-high voltage main transmission line
Selection suggestions	General pressure first choice	Best value for medium pressure	High-pressure transmission, pursuing weight reduction	High-pressure transmission, higher strength	Ultra-high pressure, pursuing extreme weight loss

API 5L X70

Products Features

Technical Specifications

Application Fields

Delivery and Customization

Why Choose Us? - Reliable Engineering Technology. Dependable Delivery.

FAQ

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