ASTM A588 Grade A / B / K
High-strength low-alloy weathering plate for welded, bolted and riveted structural members, including bridge and building fabrication.
Global Steel Supply & Processing
Weathering steel plate for bridges, outdoor structures, architectural cladding and industrial projects. Compare ASTM, EN, GB and JIS grades, then specify your plate dimensions, quality class and inspection requirements for a factory quotation.
Share the governing standard, grade, thickness, width, length, quantity and project environment. Our team will review the requested plate supply and documentation details.
Explore weathering steel grades ↓
Choose the material family and governing standard stated in your project documents. Grade chemistry, impact class, product thickness and delivery condition determine the final acceptance requirements.
High-strength low-alloy weathering plate for welded, bolted and riveted structural members, including bridge and building fabrication.
ASTM A588/A588M-24 · Up to 200 mm scopeWeathering structural plate and shapes for projects where strength, durability and exposed surface performance are specified.
ASTM A242/A242M-24 · Product thickness scope appliesHot-rolled or cold-rolled weathering sheet and strip, including coil product forms for architectural and formed components.
ASTM A606/A606M-25 · Type 4Bridge structural steel specification with weathering-grade requirements. Confirm the bridge design code, toughness and supplementary testing scope.
ASTM A709/A709M-26 · Bridge applicationEuropean weathering structural grades with quality classes defined by impact requirements and thickness-dependent mechanical properties.
EN 10025-5:2019 · W gradesHigher-phosphorus weathering grades for the flat-product scope defined by EN 10025-5. Specify the exact quality and thickness.
EN 10025-5:2019 · WP gradesChinese weathering structural steel grades for plates, strips and structural components, with strength and impact requirements by grade.
GB/T 4171-2008 · GB/T 34560.5-2017High-weather-resistance steel grades for selected outdoor structural and formed applications. Confirm the required grade and product form.
GB/T 4171-2008 · GNH familyJapanese atmospheric-corrosion-resisting rolled steels for welded structures, with quality suffixes and mechanical requirements by grade.
JIS G 3114 · Current editionInclude grade, standard and edition, thickness, quality class, delivery condition and any impact-test temperature in your RFQ. Cross-standard comparisons are reference points for engineering review; material acceptance follows the selected specification.
Weathering steel product standards define grade chemistry, mechanical properties, impact quality and delivery conditions. Select the product form and governing standard together.
High-strength low-alloy structural steel plate, shapes and bars with atmospheric corrosion resistance.
High-strength low-alloy structural steel for welded, riveted and bolted construction with improved atmospheric corrosion resistance.
Hot-rolled and cold-rolled HSLA sheet and strip with improved atmospheric corrosion resistance, including Type 4.
Structural steel for bridges, including weathering grades such as Grade 50W.
Technical delivery conditions for hot-rolled structural steels with improved atmospheric corrosion resistance.
Atmospheric corrosion-resisting structural steel. Current national edition as of 2 November 2026.
Structural steels — Part 5: technical delivery conditions for atmospheric corrosion-resisting steels.
Hot-rolled atmospheric corrosion-resisting steels for welded structures, including SMA grade families.
Guide for estimating atmospheric corrosion resistance of low-alloy steels using exposure and chemistry-based methods.
GB/T 4171-2008 and GB/T 34560.5-2017 remain current on 2 November 2026. A national revision project for the weathering-steel delivery standard is under approval; confirm the governing edition stated in your purchase order.
Use this table to identify the relevant specification family. Strength, impact and chemistry values are controlled by the exact grade, thickness and quality class.
| Grade / Family | Standard | Product Form | Key Purchasing Detail |
|---|---|---|---|
| ASTM A588 Grade A / B / K | ASTM A588/A588M-24 | Plate, shapes, bars | Grade chemistry and thickness-dependent tensile requirements |
| ASTM A242 Type 1 | ASTM A242/A242M-24 | Plate, shapes, bars | Confirm applicable product thickness and construction requirements |
| ASTM A606 Type 4 | ASTM A606/A606M-25 | Sheet, strip, coil | Type 4 chemistry and coil-product testing requirements |
| ASTM A709 Grade 50W | ASTM A709/A709M-26 | Bridge plate and structural products | Bridge code, toughness, supplementary testing and traceability |
| S355J0W / S355J2W / S355K2W | EN 10025-5:2019 | Flat and long products | J0, J2 or K2 impact quality and thickness range |
| S355J0WP / S355J2WP | EN 10025-5:2019 | Flat products | WP chemistry class and its defined product-thickness scope |
| Q235NH / Q355NH / Q415NH | GB/T 4171-2008 | Plate, strip, sections | Grade, quality suffix, thickness and impact requirements |
| Q265GNH / Q355GNH | GB/T 4171-2008 | Plate, strip, formed products | High-weather-resistance grade family and product form |
| SMA400AW / SMA490AW / SMA570W | JIS G 3114 | Hot-rolled welded-structure steel | Grade, quality suffix and impact-test requirement |
Grade comparison is for specification identification. A588, S355J2W, Q355NH and SMA490AW are separate standard designations; any substitution or dual certification requires full compliance review against both standards.
Mechanical requirements change with plate thickness, grade and quality class. Use the values in the material standard and the test report for final design acceptance.
| Specification | Thickness | Minimum Yield Strength | Tensile / Impact Reference |
|---|---|---|---|
| ASTM A588 plate | t ≤ 100 mm | 345 MPa | 485 MPa minimum tensile strength |
| ASTM A588 plate | 100 < t ≤ 125 mm | 315 MPa | 460 MPa minimum tensile strength |
| ASTM A588 plate | 125 < t ≤ 200 mm | 290 MPa | 435 MPa minimum tensile strength |
| EN S355J2W | t ≤ 16 mm | 355 MPa | 27 J at −20°C for J2 quality |
| GB Q355NH | t ≤ 16 mm | 355 MPa class | Confirm thickness band and quality suffix |
ASTM A588 values above are reference plate requirements; grade, thickness and specimen conditions govern the applicable table. EN and GB values are shown for the stated thickness band only. Confirm all acceptance values against the ordered edition and MTC.
Weathering steel contains controlled alloying elements that support the development of a dense oxide layer during suitable outdoor exposure. Repeated wet-and-dry cycles help the surface patina mature and slow further atmospheric corrosion.
Select the grade and quality class for the structural design, exposure conditions, fabrication route and inspection requirements of your project.
Weathering structural plate for bridge girders, deck components, cross frames and infrastructure fabrication under the governing bridge specification.
Plate and sheet for exterior cladding, landscape structures, canopies and architectural features where the patina appearance is part of the design.
Structural plate and formed components for railway wagons and transport equipment.
Outdoor frames, support members and structural assemblies specified for atmospheric exposure.
Selected tower, support and utility structures with project-specific material requirements.
Planters, screens, sculpture bases and exterior design components using natural patina.
Weathering sheet and plate for selected transport, storage and industrial equipment.
Cut plate, stiffeners, brackets and welded parts to your approved fabrication drawings.
Weathering steel performance depends on atmospheric conditions, wet-and-dry cycles, drainage, chloride deposits and structural detailing. ASTM G101 provides methods for estimating atmospheric corrosion resistance; project suitability remains an engineering decision.
Coordinate grade identification, plate dimensions, inspection records and export arrangements through one purchasing enquiry.
Company-wide annual steel production reaches 8 million metric tons across the product portfolio, supporting broad industrial supply coordination.
Manufacturing Overview ↗Regular company-wide steel inventory is approximately 1 million metric tons. Specific weathering grades, thicknesses and dimensions are checked by enquiry.
Inventory Overview ↗Define the governing standard, grade, heat traceability, mechanical tests, impact class and dimensional checks for your ordered plates.
Quality Control ↗Include plate sizes, tonnage, packing preferences and destination details for a coordinated commercial offer.
Weathering plate orders require grade-specific chemistry, rolling and delivery condition, thickness control and traceable test documentation. Share your plate schedule so the requested supply route can be reviewed against your project specification.
Send your grade list and dimensional schedule for a stock and production review. Our company-wide steel inventory is approximately 1 million metric tons across product categories; specific weathering plate grades and sizes are confirmed by enquiry.
Set the acceptance scope against the selected product standard, grade and purchase order. Weathering performance, strength, toughness and dimensions are verified through the applicable material tests and documentation.
Send your part drawings and required tolerances with the grade specification. Processing feasibility and the suitable cutting method are reviewed according to plate thickness, geometry and fabrication requirements.
Estimate theoretical plate weight using a nominal steel density of 7,850 kg/m³. Enter the plate dimensions and quantity to plan your material tonnage.
Formula: thickness × width × length × density ÷ 1,000,000,000 = kg per plate. This is a theoretical estimate for purchasing and transport planning.
| Plate Size (mm) | Qty. | Estimated Total |
|---|---|---|
| 10 × 2,000 × 6,000 | 10 | 9.420 MT |
| 12 × 2,200 × 8,000 | 5 | 8.294 MT |
| 16 × 2,200 × 10,000 | 4 | 11.052 MT |
| 20 × 2,500 × 12,000 | 3 | 14.130 MT |
Reference calculations use 7,850 kg/m³. Actual mass follows the supplied plate dimensions, applicable tolerances and agreed commercial weighing terms.
Weathering plate packing is arranged around the surface condition, plate dimensions, handling method and transport route. Specify your storage and surface appearance requirements before dispatch.
Continue to related plate categories, material families and company supply resources.
Answers for grade selection, patina development, inspection and bulk procurement.
Weathering steel is a low-alloy structural steel designed to develop a protective oxide patina under suitable atmospheric exposure. Its alloy chemistry supports improved atmospheric corrosion resistance compared with conventional carbon structural steel.
Common enquiries include ASTM A588 Grade A/B/K, ASTM A242 Type 1, EN S355J0W/S355J2W/S355K2W, GB Q235NH/Q355NH/Q355GNH and JIS SMA400W/SMA490W families. State the exact grade and standard in your RFQ.
Corten is commonly used as a trade name for weathering steel products. ASTM A588, A242, EN 10025-5 and other standards define specific material requirements. Specify the governing standard and grade on the purchase order.
The surface patina develops through repeated wetting and drying in a suitable atmosphere. The color and maturity of the surface evolve with exposure conditions, drainage, humidity and time.
Uncoated use can be considered in suitable environments with effective drainage and regular drying. Marine chloride exposure, persistent wetness, soil contact and trapped moisture require a project-specific corrosion assessment and protection strategy.
Common specifications include ASTM A588/A588M, A242/A242M, A606/A606M, A709/A709M, EN 10025-5, GB/T 4171 and JIS G 3114. Select the standard that matches your product form and project design code.
Specify the MTC, heat analysis, tensile test, impact test, dimensional inspection, ultrasonic testing and third-party inspection scope as required by your purchase specification.
Provide grade, standard edition, thickness, width, length, quantity, delivery condition, impact-test requirements, inspection scope and destination port. Add the project environment when uncoated service is specified.
Send your required grade, dimensions, quantity and destination. Our team will review the inquiry.