GB steel pipes

GB steel pipes

Chinese National Standard Industrial Solutions

High-quality steel pipes manufactured to Chinese GB standards, ensuring superior strength, durability, and reliability for diverse industrial applications including construction, fluid transport, and energy sectors.

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National Standard Manufacturers

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Seamless Pipe Units

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Major GB Standards

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% Quality Compliance

What are GB Steel Pipes?

GB Steel Pipes refer to steel pipes manufactured in China according to specific national standards known as GB (Guobiao) standards.

These comprehensive standards rigorously regulate the production, quality, and testing of steel pipes, ensuring their safety, reliability, and consistent performance across a wide array of applications. GB steel pipes are typically produced from ingots or solid billets through processes such as piercing, followed by hot rolling, cold rolling, or cold drawing, resulting in seamless or welded configurations.

Key Features

National Standard Compliance

Fully adheres to stringent Chinese GB standards, guaranteeing consistent quality, safety, and reliability for all products.

Superior Strength & Durability

Manufactured from high-quality steel, offering exceptional mechanical properties and long-lasting performance.

Versatile Applications

Widely used across diverse sectors including construction, fluid transport, boiler systems, and chemical industries.

Comprehensive Technical Requirements

GB standards encompass detailed specifications for chemical composition, mechanical properties, and testing methods.

Strict Quality Control

Mandates thorough inspection including non-destructive testing, hydrostatic testing, and surface inspection.

Traceability & Certification

Requirements for packaging, marking for traceability, and quality certificates verify compliance with standards.

Major GB Steel Pipe Standards

GB/T 8162-1999
Structural seamless steel pipe

General and mechanical structural applications; materials like 20, 45, Q345, 20Cr, 40CrMo.

Structural Mechanical
GB/T 8163-1999
Fluid conveying seamless pipe

For conveying fluids in pipelines and large equipment; typical grades: 20, Q345.

Fluid Engineering
GB 3087-1999
Low-/medium-pressure boiler tubes

Used in boilers; materials include 10 and 20 steel grades.

Boiler Medium Pressure
GB 5310-1995
High-pressure boiler tubes

For high-temp, high-pressure boiler systems (e.g., 20G, 12Cr1MoVG, 15CrMoG) :contentReference[oaicite:1]{index=1}

High Pressure Power Plants
GB 5312-1999
Marine boiler/superheater pipes

Specified for ships; grades include 360, 410, 460 steels :contentReference[oaicite:2]{index=2}.

Marine Shipbuilding
GB 9948-1988
Petroleum cracking pipelines

For refineries, heat exchangers; typical materials 20, 12CrMo, 1Cr5Mo, etc. :contentReference[oaicite:3]{index=3}

Petroleum Heat Exchanger

Stainless Steel GB Standards

GB13296‑2023
Seamless tubes for boiler & heat exchanger

Applies to austenitic & ferritic stainless steel, OD 6–630 mm, WT 1–14 mm, lengths up to 12 m. Covers dimensions, tolerances, inspection, packaging, and marking per GB/T 13296‑2023.

GB/T14975‑2012
Seamless stainless tubes for structure

Covers stainless tubes for general structural/mechanical use, includes size, test methods, inspection, packaging, and marking.

GB/T14976‑2012
Seamless stainless tubes for fluid transport

Targets fluids conveying systems; specifies technical/inspection rules; suitable for corrosive media transport.

FAQ

GB steel pipes, under GB/T 8162, are seamless carbon steel pipes designed for structural and mechanical applications in construction, machinery, and automotive industries.

Common grades include 10#, 20#, 35#, 45#, and Q345B, with Q345B widely used for its strength and toughness.

For Q345B:
- C ≤0.20%; Si ≤0.55%; Mn 1.00–1.60%; P ≤0.040%; S ≤0.035%

For Q345B:
- Yield Strength: ≥345 MPa
- Tensile Strength: 470–630 MPa
- Elongation: ≥21%

Outer diameters range from 6–426 mm; wall thicknesses 1–50 mm; lengths typically 6–12 m. Tolerances: OD ±1%, wall thickness ±12.5%.

Produced via hot-rolling or cold-drawing; optional treatments include normalization, phosphating, or galvanizing for enhanced properties.

Includes tensile, impact, hydrostatic, and dimensional inspections to ensure quality and compliance.

Used in construction, machinery manufacturing, automotive components, pressure vessels, and general engineering.

Marked with standard, grade, OD×WT, heat number, and manufacturer ID near ends. Orders specify standard, grade, dimensions, length, and test certificates.

Common equivalents include:
- 20# ≈ ASTM A106 Grade B
- Q345B ≈ ASTM A572 Gr.50
- Q345B ≈ EN 10025 S355

20G seamless pipe, commonly associated with GB/T 5310 for high-pressure boiler applications, is also used under GB/T 8162 for structural purposes. It is a low-carbon steel grade (20#) known for its good strength, toughness, and weldability, suitable for mechanical and structural applications.

For 20G (GB/T 8162):
- Chemical Composition: C 0.17–0.23%; Si 0.17–0.37%; Mn 0.35–0.65%; P ≤0.035%; S ≤0.035%
- Mechanical Properties: Yield Strength ≥235 MPa; Tensile Strength 410–550 MPa; Elongation ≥24%

20G seamless pipes are used in structural frameworks, machinery components, automotive parts, and low-pressure boiler systems, leveraging their excellent weldability and moderate strength.

20G has lower carbon content (0.17–0.23% vs. ≤0.20%) and yield strength (≥235 MPa vs. ≥345 MPa) than Q345B, making it more suitable for applications requiring better weldability and moderate strength, while Q345B is preferred for higher load-bearing structures.

20G seamless pipes are manufactured via hot-rolling or cold-drawing, with optional treatments like normalization or annealing to improve toughness and surface quality, ensuring suitability for structural and boiler applications.

Industrial Applications

GB/T 8162 seamless steel pipes are essential for industries requiring high strength, durability, and machinability in structural and mechanical applications.

Construction Industry

Used in structural frameworks, bridges, and building supports.

Machinery Manufacturing

Applied in machinery components and precision equipment.

Automotive Industry

Used in chassis, axles, and other structural components.

Shipbuilding

Marine applications for structural elements, fluid systems, and critical components requiring durability.

Petroleum & Chemical

Refineries, petrochemical plants, and chemical processing facilities for handling various substances.

General Engineering

Used in various engineering applications requiring seamless tubing.

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