Corten Steel Plate
Atmospheric corrosion resistant plate that builds its own protective rust instead of paint
Specifications
Alloy Steel Sheet
SPAH Weather Resistant Steel Plate and Thin Gauge Sheet
SPA-H grade weathering plate for bare exposed and long recoating interval structures
SPA-H corten steel plate is the JIS designation for atmospheric corrosion resistant weathering steel, a low alloy series positioned between carbon steel and stainless steel. Copper nickel and similar additions to an ordinary carbon steel base let the surface turn its first rust into a dense film that slows what follows, while strength ductility forming welding abrasion and high temperature behavior stay close to a comparable structural steel. Buyers reach for SPA-H specifically when a drawing or a customer specification names that grade and an offer of Q355NH or S355W will not clear inspection. We roll it from 0.1mm to 10mm so thin sheet work and plate fabrication can be covered on the same order rather than split between a sheet supplier and a plate mill.
- Product Name — SPA-H Corten Steel Plate
- Also Known As — SPA-H weather resistant steel plate weathering steel
- Material — Q235NH Q355NH SPAH 09CuPCrNi-A Grade K S235W S355W
- Grade — SPAH and equivalents Q235NH Q355NH 09CuPCrNi-A Grade K S235W S355W
- Standards — BS EN GB AISI ASTM DIN JIS
Why It Is Specified
Key Benefits of SPA-H Corten Steel Plate
Certified Under the SPAH Grade Designation
When the specification says SPA-H the material is certified as SPA-H, with Q235NH Q355NH 09CuPCrNi-A Grade K S235W and S355W available where an equivalent is acceptable.
Thin Gauge Sheet a Plate Mill Will Not Roll
The range starts at 0.1mm, which covers light panel and sheet work that a plate mill will not quote, and runs through to 10mm for structural parts.
Spot Welding Possible on Thin Material
Thin SPA-H sheet accepts spot welding as well as manual and submerged arc welding, so panel assembly stays on the equipment a sheet metal shop already has.
Recoating Cost Reduced Where Paint Is Used
The coating film has a long life on weathering steel, and paintability is stated at 1.5-10 times that of ordinary carbon steel.
Bare Exposure Gives a Finished Appearance
Left uncoated the plate develops the sedate color of the protective rust, which several highway and architectural specifications accept as the final finish.
Three Delivery Conditions
Plate is available Q+T hot rolled or normalized so the mechanical condition can be matched to the fabrication route rather than accepted as given.
Problems It Solves
What This Material Removes From Your Process
Specification Names SPAH and Stock Says Otherwise
Inspectors reject material certified to a different designation even when the chemistry is close. Ordering the grade the drawing names avoids the argument on delivery.
Thin Weathering Gauges Are Hard to Source
Most weathering steel is offered as structural plate. Rolling from 0.1mm covers the panel work that usually gets refused.
Joining Light Panels Without Distortion
Arc welding thin sheet buckles the panel. Spot welding is possible on thin SPA-H material, which keeps the face flat.
Paint Systems Failing Early on Exposed Steel
A coating on ordinary carbon steel breaks down and pulls the asset into an early repaint. On weathering steel the film lasts longer and the steel underneath is not defenseless when it wears through.
Two Suppliers for One Weathering Package
Splitting sheet and plate between suppliers creates two certificates and two delivery dates. One order across the 0.1mm to 10mm range keeps the package together.
Application Scenarios
Where It Is Used
Bridge Structural Members
Beams stiffeners and connection plates on bridge work written to a weathering steel specification.
Guard Rail Sections
Formed guard rail and barrier components that live in road spray without a maintained coating.
Sign Poles and Support Frames
Poles brackets and frames along highways, fabricated from plate and left bare once installed.
Thin Sheet Panel Fabrication
Light gauge panels down to 0.1mm pressed or folded and joined by spot welding where the rust finish is wanted.
Highway Structures and Roadside Equipment
Cabinets housings and posts on highway projects that would otherwise need a maintained paint system.
Painted Assets on a Long Maintenance Cycle
Coated structures where the owner is buying the long coating film life rather than a bare weathered surface.
Who It Is For
Buyers Who Specify This Product
- Fabricators holding a customer specification that names SPA-H and will not accept a substitute
- Sheet metal shops buying weathering steel in gauges a plate supplier will not roll
- Highway and bridge contractors buying guard rail sign pole and structural components
- Design engineers comparing bare weathering steel against a painted carbon steel maintenance plan
- Export traders supplying weathering steel into markets that quote JIS designations
- Project buyers consolidating thin sheet and plate onto one weathering steel order
Technical Data
Specifications and Technical Features
Values below come from the product data published by Shandong Tianyu Metal Products. Confirm the exact grade and size against your order.
| Product Name | SPA-H Corten Steel Plate |
|---|---|
| Also Known As | SPA-H weather resistant steel plate weathering steel |
| Material | Q235NH Q355NH SPAH 09CuPCrNi-A Grade K S235W S355W |
| Grade | SPAH and equivalents Q235NH Q355NH 09CuPCrNi-A Grade K S235W S355W |
| Standards | BS EN GB AISI ASTM DIN JIS |
| Thickness | 0.1-10mm |
| Thickness Customized | 0-100mm |
| Width | Customized as required |
| Size | Customized |
| Technique | Q+T hot rolled normalized |
| Surface | Nature or painted |
| Application | Bridges guard rails sign poles highway structures |
| Place of Origin | China |
| Processing Service | Bending welding decoiling cutting punching |
| Certificate | Mill test certificate |
Technical Features
- SPA-H atmospheric corrosion resistant weathering steel
- Equivalents Q235NH Q355NH 09CuPCrNi-A Grade K S235W and S355W
- Standards BS EN GB AISI ASTM DIN and JIS
- Thickness 0.1mm-10mm or customized as required
- Technique Q+T hot rolled or normalized
- Spot welding possible on thin material and arc welding on heavier sections
- Paintability stated at 1.5-10 times ordinary carbon steel
- Processing service bending welding decoiling cutting and punching
Materials
- SPA-H weathering steel to the Japanese designation
- Carbon steel base with copper nickel and other corrosion resistant elements
- Equivalent grades Q235NH Q355NH 09CuPCrNi-A Grade K S235W and S355W
- Supplied Q+T hot rolled or normalized
Certification
- Mill test certificate supplied with each shipment
Manufacturing
How It Is Made and Processed
Steelmaking to the SPA-H chemistry with corrosion resistant additions
Hot rolling down to the ordered gauge
Normalizing or quenching and tempering where the delivery condition calls for it
Decoiling and leveling for thin gauge material
Cutting to sheet or plate size including gas cutting
Cold or hot forming bending and punching to the drawing
Packing with edge protection and loading for export
Quality Control
Checks Before It Ships
- Mill test certificate issued under the SPA-H designation as ordered
- Gauge measured across the sheet before cutting
- Delivery condition recorded as Q+T hot rolled or normalized
- Cut sizes checked against the fabrication list
- Surface inspected for scratches and handling marks on thin gauge material
- Bundles marked so grade is identifiable after the plate begins to weather
Customization
What We Can Change on Your Order
- Gauge selected from 0.1mm sheet through to 10mm plate
- Certified as SPA-H or against the equivalent grade your inspector accepts
- Delivery condition specified as Q+T hot rolled or normalized
- Sheets and plates cut to the fabrication list before shipment
- Forming and punching carried out on guard rail post and panel components
- Supplied bare for weathering or painted where the project calls for a coating
Comparison
SPA-H Corten Steel Plate Against the Alternatives
| Ordinary carbon steel sheet | The alloy additions convert early rust into a protective film, where a plain carbon sheet keeps losing section until it is coated. |
|---|---|
| Hot dip galvanized sheet | No zinc coating means no burn back at welds and no touch up after cutting, and spot welding on thin material stays straightforward. |
| Stainless steel sheet | SPA-H is a low alloy weathering series, not a stainless grade, and covers exposed structural and panel work at a lower material cost. |
| Generic weathering plate offered as an equivalent | Where a specification names SPA-H the certificate matters as much as the chemistry, and material can be ordered and certified under that designation. |
Use Guide
Specifying Handling and Welding Notes
- Confirm whether your inspector will accept an equivalent grade before ordering against a substitute
- Detail joints so water drains and does not pond on horizontal surfaces during weathering
- Use spot welding on thin sheet and manual or submerged arc welding on the heavier gauges
- Treat cold working hot working and gas cutting as you would on a carbon steel of the same strength level
- Allow for the surface color changing over the first exposure period before it settles
- Ask for the mill test certificate at order stage so the SPA-H grade is documented before the plate ships
Questions Buyers Ask
SPA-H Corten Steel Plate FAQ
Do you certify the plate as SPA-H or as an equivalent?
Material can be certified under the SPA-H designation. Where your inspector accepts an equivalent we can also supply Q235NH Q355NH 09CuPCrNi-A Grade K S235W or S355W.
What is the thinnest gauge you can roll?
0.1mm, which covers panel and sheet work, and the range runs to 10mm for plate. Customized sizes outside that are quoted on the drawing.
Can thin SPA-H sheet be spot welded?
Yes. Spot welding is possible for thin materials, and manual or submerged arc welding is used on heavier sections.
Is SPA-H the same material as corten steel?
SPA-H is one of the weather resistant grades in the corten family, an atmospheric corrosion resistant low alloy steel that sits between carbon steel and stainless steel.
What delivery conditions are available?
Q+T hot rolled and normalized. Tell us the fabrication route and we will confirm which condition suits the forming and welding you plan.
How does it behave if we paint it anyway?
The coating film has a long life and paintability is stated at 1.5-10 times that of ordinary carbon steel, so the recoating cost over the life of the asset is lower.
Can you punch and form guard rail and post sections?
Yes. Bending welding decoiling cutting and punching are all available, so components can arrive formed and drilled to your drawing.
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