GB/T 4171 Q460NH Weathering Steel Plate (Corten Steel Plate)

Q460NH Weathering Steel Plate (Corten Steel Plate) is a premium weldable steel that combines high strength (yield strength ≥ 460 MPa) with excellent weathering resistance. It is particularly suitable for various engineering structures exposed to atmospheric environments over long periods.

By adding alloying elements such as Cu, Cr, and Ni, a self-protective rust layer is formed, significantly extending the service life, reducing maintenance costs, and providing unique aesthetic value to structures.

An appropriate quality grade (A/B/C/D/E) should be selected based on the engineering application environment (e.g., humidity, salt spray, temperature). For thicknesses > 16 mm, attention should be paid to preheating requirements during welding, and welding procedure qualification is recommended for large structures.

Key Features and Advantages

1. Excellent Weather Resistance

The surface forms a dense and stable oxide layer that prevents further corrosion. Its weather resistance is 2–8 times higher than that of ordinary carbon steel.

In a simulated coastal industrial environment, the corrosion rate is reduced by 63.8% compared to ordinary carbon steel.

2. High Strength and Lightweight

Yield strength ≥ 460 MPa, tensile strength between 570–730 MPa, making it suitable for heavy-duty structures. It reduces material usage and weight while maintaining equivalent strength, especially ideal for large structures with weight and strength requirements.

3. Excellent Processing Performance

Good weldability, cold bending, and formability, suitable for various processing methods.

Conventional welding materials and processes can be used (attention should be paid to requirements such as preheating).

4. Maintenance-Free Characteristic

Weathering steel can be used exposed in specific environments. After forming a stable rust layer on the surface, no painting or maintenance is required. Its service life can exceed 50 years, significantly reducing long-term maintenance costs.

5. Unique Aesthetic Value

Its distinctive reddish-brown rust layer offers a certain artistic effect (commonly used in building facades and art sculptures).

Carbon Equivalent (CEV) of Q460NH Weathering Steel Plate (Corten Steel Plate) : ≤ 0.50%

* Calculate using the standard formula recommended by the International Institute of Welding (IIW): CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15

Note: "a" is the thickness of the steel material

Impact Energy

* The main difference lies in the varying impact test temperature requirements, ranging from Grade A (no requirement) to Grade E (-40°C), with progressively increasing demands for low-temperature toughness.

Thanks to its high strength and corrosion resistance, Q460NH weathering steel plate (corten steel plate) is commonly used in structures requiring high durability and strength in outdoor or corrosive environments, such as:

1. Bridge Engineering

Cross-sea bridges, urban viaducts, railway bridges, etc., especially suitable for marine and humid environments.

2. Architectural Structures

Building facades, roofs, and support structures, offering a unique rusted aesthetic appeal.

3. Transportation Equipment

Railway vehicles, containers, and highway guardrails.

Its corrosion resistance reduces maintenance frequency and extends service life.

4. Energy Facilities

Wind power tower cylinders, power transmission towers, designed to withstand harsh outdoor environments.

Weathering properties ensure long-term safe and stable operation.

5. Landscaping and Art

Urban sculptures, garden landscapes (feature walls, trellises), and public facilities (guardrails).

The unique rust-colored texture evolves over time, adding artistic value.

Precautions for Usage and Fabrication

1. Initial rusting stage:

During the early stages of exposed use (approximately 1–3 years), rust runoff may occur with rainwater, potentially staining adjacent walls or ground. Drainage or redirection measures should be considered in the design to accommodate this temporary appearance. Once a stable rust layer forms, runoff will cease.

2. Not suitable for long-term immersion or high-salt environments:

The advantage of weathering steel lies in its performance under wet-dry cycling atmospheric conditions. However, if subjected to prolonged immersion in water or exposure to marine splash zones, its corrosion resistance is not significantly superior.

3. Welding process:

Strict welding procedures must be established:

a) Use low-hydrogen or ultra-low-hydrogen electrodes.

b) Apply appropriate preheating and control interpass temperatures.

4. Cutting:

Methods such as flame cutting, plasma cutting, or laser cutting can be used. The hardened layer at the cut edge may slightly affect corrosion resistance; for critical structures, grinding treatment is recommended.

5. Surface treatment:

Natural rusting: Requires 1–3 years to form a stable protective rust layer. Initial rust may be uneven and prone to flaking.

Artificial accelerated treatment: Chemical or electrochemical methods can be used to quickly form a uniform rust layer.

6. Avoid contact with carbon steel to prevent galvanic corrosion.

It is recommended to use connecting components made of the same material or stainless steel.

Quality Grade Selection Guide

Comparison with Similar Steel Grades

Note: The same series of "GNH" grades (e.g., Q355GNH) are high weather resistance grades, offering better weather resistance but slightly poor weldability.