Gnee Completes Export Of 1528.290 Tons ASTM A709 Grade 50W Weathering Steel Pipes To Thailand

01/06/2026

Gnee (Tianjin) Multinational Trade Co., Ltd has successfully completed the export of 1528.290 tons of ASTM A709 Grade 50W weathering steel pipes to Thailand, supporting the country’s ongoing national infrastructure development program.

The pipes will be used in bridge, viaduct, and water transmission systems, marking another milestone in Gnee’s continued expansion into Southeast Asia.

Product Overview

ASTM A709 Grade 50W weathering steel is a high-strength, low-alloy structural steel designed for use in bridges and other structures requiring both mechanical durability and resistance to atmospheric corrosion.

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Compared with conventional carbon steels, A709 Gr.50W develops a protective oxide film on the surface during exposure, which slows further corrosion and provides a maintenance-free service life of over 30 years in open-air or coastal environments.

Key Advantages:

Long-term corrosion resistance in tropical climates

High tensile strength with excellent toughness

Reduced maintenance costs (no need for frequent repainting)

Environmentally sustainable – minimal coating or solvent use

Chemical Composition (%):

Element	C	Mn	Si	P	S	Cu	Cr	Ni
Content	0.15	1.25	0.33	0.06	0.03	0.36	0.55	0.38

The alloying elements Copper (Cu), Chromium (Cr), and Nickel (Ni) promote the formation of a dense oxide patina, which is the core of its weathering property.

Mechanical Properties

Property	Requirement	Gnee Test Result	Remark
Yield Strength	≥345 MPa	355 MPa	Uniform across all batches
Tensile Strength	485–635 MPa	540 MPa	Excellent consistency
Elongation	≥18%	20%	Good ductility and formability
Impact Energy (–20°C)	≥27 J	32 J	Superior low-temperature toughness

All results were verified according to ASTM A370 mechanical testing standards, ensuring compliance and reliability for bridge-grade applications.

Applications

A709 Gr.50W weathering steel pipes are highly suitable for structural and infrastructure projects exposed to natural weather conditions.

Application	Description
Bridge and Viaduct Construction	Used for main truss members, guard rails, and drainage systems on long-span bridges.
Highway Safety Barriers	Provides both structural integrity and visual harmony with natural surroundings.
Water Transmission Pipelines	Used in urban drainage and irrigation projects, offering corrosion-free long life.
Architectural Outdoor Elements	Popular in sculptures, façades, and landscape edging due to its rustic appearance.

These pipes offer a minimum design life of 50 years in rural or coastal exposure without repainting, making them ideal for Thailand’s humid tropical climate.

Production Process

Gnee’s A709 Gr.50W pipes are manufactured under ISO 9001:2015-certified facilities, following a controlled hot-rolling and welding process to achieve structural precision and consistent properties.

Manufacturing Workflow:

Raw Material Selection:
High-quality weathering steel slabs (50W grade) tested for composition accuracy.

Hot Forming:
Rolled into specified diameters under 900–950°C for uniform grain structure.

Welding & Heat Treatment:
Pipes welded with low-hydrogen electrodes, followed by normalization to improve toughness.

Dimensional Inspection:
Wall thickness, ovality, and straightness verified using laser measurement systems.

Surface Preparation:
Blasting and pickling to remove oxides before oil coating.

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Inspection & Testing

Test Type	Description	Standard	Result
Ultrasonic Test	100% volume check for internal flaws	ASTM A435	Passed
Hydrostatic Test	70 MPa pressure test	ASTM A530	Passed
Salt Spray Test	500-hour corrosion simulation	ASTM B117	Passed
Charpy Impact Test	Low-temperature impact performance	ASTM A370	Passed
Third-Party Audit	SGS inspection & sampling	EN 10204 3.1	Approved

All data and inspection reports were reviewed by both Gnee Quality Control Department and SGS, ensuring full compliance with client specifications.

Packaging & Logistics

Gnee places great emphasis on packaging integrity and cargo protection during international shipping. Each pipe was carefully processed before departure.

Item	Details
Total Shipment Weight	1528.290 tons (12 batches)
Origin Port	Tianjin Xingang, China
Destination Port	Bangkok, Thailand
Estimated Transit Time	16 days
Packaging Method	Anti-corrosion oil coating + waterproof plastic + steel banding
Container Type	40′ HQ bulk containers
Documents Provided	MTC EN 10204 3.1, Packing List, Inspection Report, SGS Certificate

Before loading, the pipes were coated with protective anti-rust oil, then wrapped in moisture-proof plastic film, and bundled with steel straps. Each bundle was tagged with heat number, size, and weight for traceability.

Upon completion, Gnee’s logistics team supervised loading operations at Tianjin Xingang Port, performing random sampling and photographic documentation. Real-time tracking was enabled during transit to ensure on-time and damage-free delivery to Bangkok Port.

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