Inquiry Now

ASME SA588 Grade K (SA588GRK) Weathering Steel Plate

Q: What is the service life of weathering steel?

Inland, dry environments: 50+ years (maintenance-free); industrial/suburban environments: 30–50 years; coastal areas with low salt spray: 15–25 years (additional corrosion protection required in areas with high salt spray).

Q: Can weathering steel be used in coastal areas or environments with high salt spray levels?

Use with caution. In environments with high salt spray levels or high chloride ion concentrations, the rust layer on standard weathering steel is easily penetrated, accelerating corrosion and potentially leading to pitting or perforation.

Q: What are the welding properties of weathering steel?

It has good welding properties and can be welded using conventional processes such as manual arc welding and gas shielded arc welding.

Q: Does weathering steel require painting?

In normal atmospheric conditions (urban or rural), painting is not required; a stable passivation layer will form after 6–18 months of exposure, providing a corrosion resistance lifespan of 80–100 years.High-humidity / highly corrosive environments (coastal areas, industrial acid rain, salt spray zones): It is recommended to apply a thin coat of weathering primer initially or to carry out regular maintenance to prevent the early loss of the rust layer.Concealed / damp, poorly ventilated areas: Waterproofing and anti-corrosion coating must be applied to prevent localised rusting from worsening.

Q: How long does it take for a rust layer (oxidation layer) to form on weathering steel?

The rate at which the oxidation layer forms depends on climatic conditions. In outdoor environments with significant fluctuations between dry and wet conditions, it typically takes between six months and two years for a stable, dark brown protective layer to form. During the initial stage, rust streaks may form, so care should be taken to protect the surrounding building surfaces.

ASME SA588 Grade K (SA588GRK) Weathering Steel Plate

info@yx-steel.com 8615837212056 Get a Quote

ASME SA588 Grade K (SA588GRK) is a high-strength low-alloy weathering steel (corten steel), known for its excellent atmospheric corrosion resistance while maintaining high strength and good toughness. It is a premium grade within the SA588 series, specifically designed for high toughness and low-temperature service applications.

Standard :
ASME SA588/SA588M
Grade :
SA588 Grade K (SA588GRK)
Thickness :
6.0 - 200.0 mm
Width :
1500.0 - 4050.0 mm
Length :
3000.0 - 15000.0 mm

Special thickness, width, and length can be negotiated separately.
We also provide customized processing services.If you have any questions, please contact us.

Overview

ASME SA588 Grade K weathering structural steel plate is an advanced engineering material that combines high strength, excellent weather resistance, and outstanding toughness. It is particularly suitable for use in low-temperature environments, applications with high seismic requirements, and structures exposed to harsh atmospheric corrosion. Its chemical composition is designed to maintain structural strength while providing low-temperature toughness, atmospheric corrosion resistance, and weldability that ordinary steels cannot match.

It is one of the preferred materials for engineers and architects when designing and constructing steel structures intended for long-term exposure to atmospheric conditions while aiming to reduce maintenance costs. If you need to build safe and reliable structures in extreme environments, SA588 Grade K is undoubtedly an ideal choice, though its higher cost must be balanced against actual performance requirements.

Grade	SA588 Grade K (SA588GRK)
Standard	ASME SA588/SA588M: High-strength low-alloy structural steel plate, sheet, and strip with atmospheric corrosion resistance
Delivery Conditions	Hot Rolled (HR), Normalized (N), Thermo-Mechanical Control Process (TMCP).
Core Features	Excellent atmospheric corrosion resistance (4 - 6 times higher than ordinary carbon steel).
Weldability	Good weldability, use low hydrogen welding processes and matching welding materials (such as the AWS E7018 series) to prevent weld cracking and maintain corrosion resistance in the weld area.
Machinability	It can be processed by conventional methods such as flame cutting, plasma cutting, cold bending, and drilling. Cold work formability is good.
Quality Control	Provide the material certificate. If required, Charpy V-notch impact test, and Z-direction property test (Grades Z15/Z25/Z35) can be added.
Application Scenarios	Bridges, building structures, towers, containers, outdoor mechanical components (requiring atmospheric corrosion resistance without the need for painting).

Core Advantages

1. Exceptional Weather Resistance

Weathering resistance is 4-6 times that of ordinary carbon steel.

Forms a stable protective rust layer, reducing or eliminating the need for painting, significantly lowering long-term maintenance costs. Its unique reddish-brown appearance is often utilized by architects for aesthetic purposes.

2. Outstanding Low-Temperature Toughness

Specifically designed for low-temperature environments, with excellent resistance to brittle fracture.

Particularly suitable for critical structures in extremely cold regions (such as Northern Europe, Canada, and Northeast China).

3. Good Weldability and Workability

Low carbon and low equivalent design minimize susceptibility to welding cold cracks.

Preheating is often unnecessary, reducing welding costs.

Compatible with various welding processes, including automatic and manual welding.

4. Uniform Performance in Thick Plates

Maintains good strength and toughness even at the center of thick sections (≤200mm).

Performance uniformity surpasses that of other grades.

Limitations

The initial material cost is higher than that of ordinary carbon steel.

In industrial environments with persistent humidity, salt spray, or severe chemical pollution, its weather resistance advantages may diminish, potentially requiring additional protection.

The run-off rust formed may initially contaminate surrounding surfaces (such as concrete), necessitating drainage considerations during design.

Chemical Composition

Grade	SA588 Grade K (SA588GRK)
Element	C	Si	Mn	P	S	Ni	Cr	Cu	V	Mo	Nb
Content (max, %)	0.17	0.25 - 0.50	0.75 - 1.35	0.040	0.050	0.40	0.40 - 0.70	0.20 - 0.40	0.01 - 0.10	0.1	0.06

Carbon Equivalent: CEV ≤ 0.47%

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

Mechanical Properties

Grade	Thickness (t) [mm]	Tensile Strength [min, MPa]	Yield Point [min, MPa]	Elongation in 200mm [min, %]	Elongation in 50mm [min, %]
SA588 Grade K (SA588GRK)	t ≤ 100	485	345	18	21
	100 < t ≤ 125	460	315	-	21
	125 < t ≤ 200	435	290	-	21

Applications

1. Bridge Construction

Load-bearing beams and gusset plates for railways and highways in cold regions

Structures exposed to harsh environments, such as cross-sea bridges

2. Architectural Structures

Seismic structures for high-rise buildings

Public buildings in earthquake-prone areas (e.g., stadiums, airports)

3. Industrial Equipment

High-temperature components, such as air preheaters and economizers

Manufacturing of railway vehicles and containers

Structural components for mining and engineering machinery in cold regions

4. Energy Facilities

Transition sections and accessories for offshore wind turbine towers

Transmission towers in extremely cold regions

5. Containers and Transport Equipment

Railway vehicles, freight containers, and wagon bodies

6. Artistic Sculptures and Landscape Design

Outdoor sculptures and landmark structures

Other Information

Usage Precautions

1. Processing Recommendations

Welding: Use low-hydrogen electrodes and follow appropriate welding procedures.

Cutting: Suitable for all conventional cutting methods (plasma, flame, etc.).

Forming: Good cold bending performance, allowing 180° bending (d=2t).

2. Application Selection Considerations

Grade K is suitable for applications requiring high safety and toughness.

As the grade with the highest performance and cost in the SA588 series, selection should be based on actual needs.

If corrosion resistance alone is the priority, Grade A, B or C may be more cost-effective.

Comparison with Other ASME SA588/SA588M Grades

Feature	Grade A	Grade B	Grade C	Grade K
Core Features	Cost-effective weathering steel	Vanadium/Niobium micro-alloyed	Easy welding	High toughness, easy welding
Carbon Content	≤0.19%	≤0.20%	≤0.15%	≤0.17%
Key Elements	No V/Nb requirement	Contains V, (Nb)	Low C, Contains V, (Nb)	Low C, contains Mo and Nb
Strength Level	≥345 MPa	≥345 MPa	≥345 MPa	≥345 MPa
Toughness	Moderate	Good	Good	Excellent (especially at low temperatures)
Weldability	Good	Good	Excellent (low or no preheat required)	Excellent (low or no preheat required)
Main Applications	General weathering structures	Common bridges or buildings	Large bridges or buildings	Low-temperature, seismic, critical structures
Cost	Low	Medium	Medium	High

International Standard Equivalence

* Approximate correspondence, verification with specific technical requirements is necessary.

Standard	Grade	Difference Description
GB/T 4171 (China)	Q355NH	Corrosion resistance and mechanical properties are similar; Q355NH has a slightly lower carbon equivalent, offering better weldability.
EN 10025-5 (Europe)	S355J2W	Weathering grade corresponds; S355J2W has an impact test temperature of -20°C, consistent with SA588 Grade C.
JIS G 3114 (Japan)	SM490AW	Mechanical properties match; SM490AW has slightly lower corrosion-resistant element content, suitable for mild corrosive environments.
ASTM A588/A588M (USA)	A588 Grade K	Fully equivalent to ASME SA588 Grade K (ASME standard originates from ASTM, applicable for pressure equipment scenarios).

FAQ

Q1:

What is the service life of weathering steel?

Inland, dry environments: 50+ years (maintenance-free); industrial/suburban environments: 30–50 years; coastal areas with low salt spray: 15–25 years (additional corrosion protection required in areas with high salt spray).

Q2:

Can weathering steel be used in coastal areas or environments with high salt spray levels?

Use with caution. In environments with high salt spray levels or high chloride ion concentrations, the rust layer on standard weathering steel is easily penetrated, accelerating corrosion and potentially leading to pitting or perforation.

Q3:

What are the welding properties of weathering steel?

It has good welding properties and can be welded using conventional processes such as manual arc welding and gas shielded arc welding.

Q4:

Does weathering steel require painting?

In normal atmospheric conditions (urban or rural), painting is not required; a stable passivation layer will form after 6–18 months of exposure, providing a corrosion resistance lifespan of 80–100 years.

High-humidity / highly corrosive environments (coastal areas, industrial acid rain, salt spray zones): It is recommended to apply a thin coat of weathering primer initially or to carry out regular maintenance to prevent the early loss of the rust layer.

Concealed / damp, poorly ventilated areas: Waterproofing and anti-corrosion coating must be applied to prevent localised rusting from worsening.

Q5:

How long does it take for a rust layer (oxidation layer) to form on weathering steel?

The rate at which the oxidation layer forms depends on climatic conditions. In outdoor environments with significant fluctuations between dry and wet conditions, it typically takes between six months and two years for a stable, dark brown protective layer to form. During the initial stage, rust streaks may form, so care should be taken to protect the surrounding building surfaces.