API 5L Grade B Carbon Steel Pipe

Specifications

Item	API 5L Gr B Seamless / Welded Steel Pipe
Standard	API 5L PSL1 / PSL2
Grade	Gr B (L245)
Outer Diameter	10.3 – 914 mm (NPS 1/8″ – 36″)
Wall Thickness	2.11 – 60 mm
Length	6 m, 12 m or customized
Section Shape	Round
Surface Treatment	Black / Sandblasting / Painting / Galvanized / 3PE / FBE
Processing Service	Bending, Welding, Cutting, Threading
Certificate	API 5L, ISO 9001, CE

What Level is Gr B?

In the API 5L standard, grades are ranked from low to high as: A, B, X42, X52, X60, X70, X80. (The number after “X” represents the minimum yield strength.)

Gr B has relatively low strength, but it offers excellent weldability, toughness, and economic benefits.

Physical Properties

Performance Indicator	Value (Minimum)
Yield Strength	245 MPa
Tensile Strength	415 MPa
Elongation	≥20% (Full-size specimen)
Impact Energy (CVN)	≥27J at -20℃ (PSL2 requirement)
Density	7.85 g/cm³
Elastic Modulus	200 – 210 GPa

Chemical Composition

Element	Content
Carbon (C)	≤0.28 (Seamless Pipe) / ≤0.26 (Welded Pipe)
Manganese (Mn)	≤1.20
Sulfur (S)	≤0.03
Phosphorus (P)	≤0.03
Silicon (Si)	≤0.45
Copper, Nickel, Chromium, Molybdenum	Each ≤0.50

PSL1 & PSL2 Comparison

PSL1 and PSL2 are two quality levels of API 5L. PSL2 has stricter requirements for mechanical properties and non-destructive testing, making it suitable for high-pressure / high-risk pipelines.

• PSL2 imposes stricter limits on P and S: P ≤ 0.025%, S ≤ 0.015%

Product Advantages

• High Strength & Good Toughness: Low yield strength, with a carbon equivalent of ≤0.43% ensuring resistance to brittleness even at low temperatures and deformation under pressure.
• Strong Versatility: Grade B steel is the preferred economical grade for low to medium pressure scenarios, and this basic line pipe adapts to most project specifications.
• Processing Adaptability & Custom Coating: Supports cutting, bending, and threading. Available surface treatments include black pipe, galvanized, 3PE, FBE, epoxy paint / coal tar epoxy coating, etc.

API 5L Gr B Seamless Steel Pipe – Unique Advantages

• No weld seam, reducing leakage risk.
• Uniform wall thickness, with more stable control for small-diameter pipes.
• Excellent corrosion resistance, especially in slightly corrosive fluid environments.

API 5L Gr B Welded Pipe (ERW/SAW Steel Pipe) – Advantages

• Capable of producing large-diameter pipes over 24″.
• Commonly used for long-distance trunk line transmission, with low cost and fast delivery.
• Higher dimensional accuracy, suitable for mass pipeline laying.

Applications

API 5L Gr B Seamless Pipe Application Scenarios

• Oil and gas transmission branch lines
• Deep-sea pipelines, permafrost zone pipelines, oil and gas field pipelines
• Low to medium pressure fluids, refinery process pipelines
• Fire protection, construction, and high-pressure water supply in factories

API 5L Gr B Welded Pipe (ERW/SAW) Application Scenarios

• Large-diameter long-distance transmission pipelines
• Power and chemical industry pipelines
• Municipal water treatment projects (cost-priority)
• Structural applications: supports, casing pipes, bridges, port piling pipes, sheet piles

Process Classification

API 5L Gr B Seamless Steel Pipe

Formed from round steel through hot rolling/cold drawing in one piece, with no weld seams throughout. It offers higher pressure resistance and better leakage prevention.

API 5L Gr B Welded Steel Pipe

Made by rolling steel plates and joining them via Electric Resistance Welding (ERW) or Submerged Arc Welding (SAW), with weld seams. It features low cost and large diameter options.

Seamless vs. Welded Pipe Comparison

Comparison Item	Seamless Pipe	Welded Pipe
Base Material	Round Steel	Steel Strip
Weld Seam	None	Longitudinal straight seam or spiral seam
Outer Diameter	10.3 – 610 mm (max. approx. 24″)	21.3 – 2032 mm (max. approx. 80″)
Wall Thickness	2.11 – 60 mm	2.11 – 100 mm
Precision	High (H8 for cold-drawn pipes)	Relatively High
Pressure Resistance	High	Slightly lower at weld seams
High-Temperature Performance	Good (≤450°C)	Relatively Good
Low-Temperature Toughness	Good	Relatively Good
Price	High (approx. 15-30% more expensive than welded pipes)	Low (ERW is the cheapest, LSAW is next)

Common Delivery Conditions

• As-rolled (AR): Pipes rolled directly from heated billets. Most economical option.
• Normalized (N): Heated to above Ac3 ~900°C, held at temperature, then air-cooled. Most recommended.
• Annealed (A): Soft state, used for softening billets (generally pre-treatment for cold drawing).
• Quenched + Tempered (Q+T): High-strength precision version with extremely high strength; X42/X52 is more recommended for this process.
• Cold Drawn + Stress Relief: Commonly used for cold-drawn pipes to remove internal stress from cold working and ensure precise dimensions.

The most commonly used and reliable delivery condition is Normalized (N), which balances strength, toughness, and stability to meet standard requirements.

Why Not All API 5L Gr B Pipes Undergo Heat Treatment?

Due to cost and standard allowances. The API 5L standard itself permits direct delivery in “as-rolled” state (for PSL1 level), while formal projects (especially PSL2 level) mandatorily require normalized state.

Why Choose Us?

• Direct Factory Supply: Source manufacturer with no middlemen markup, stable supply, high cost-effectiveness, and 24/7 online quotation service.
• Comprehensive Certifications: API 5L, CE, ISO 9001, JIS, SNI certified, meeting qualification requirements for global exports.
• Complete Specifications: Regular stock of full-diameter, full-wall-thickness, and full-SCH grade products, including seamless pipes, ERW/SAW welded pipes (both PSL1 and PSL2 levels).
• Customization Support: Provide OEM/ODM services, including customized fixed-length, pipe end beveling, 3PE anti-corrosion, epoxy coating, etc.