SPA-C Cold Rolled Weathering Steel Coil & Sheet | Premium Corten Equivalent for Precision Fabrication
SPA-C is a premium cold-rolled weathering steel specified under the Japanese standard JIS G 3125. Designed for high-precision, lightweight applications, it is supplied in much thinner gauges (typically 0.6mm to 1.5mm) than its hot-rolled counterpart (SPA-H). Delivered strictly in an Annealed and Skin-passed condition, SPA-C offers exceptionally smooth surface quality, superior deep-drawing formability, and a highly uniform aesthetic rust patina. It is the ultimate Corten-equivalent material for architectural facades, lightweight corrugated roofing, and precision stamped parts.
100% Traceability and Mill-Direct Supply
At GNEE STEEL, we refuse to compromise on raw materials. Our SPA-C cold-rolled weathering steel is sourced exclusively from state-owned mega-mills like Maanshan Iron & Steel and Baosteel. Every coil is delivered with its original heat number, chemical composition tracking (Cu, Cr, P, Ni), and a verifiable MTC, ensuring 100% transparency and compliance with JIS G 3125 standards.
Decoding Our SPA-C Mill Test Certificate (MTC): Proof of Premium Quality
The image above is an authentic EN 10204 3.1 Inspection Certificate from our recent shipment of 1.10mm SPA-C cold-rolled weathering steel coils, manufactured by Maanshan Iron & Steel (a top-tier Chinese mill).
For overseas buyers who cannot read the Chinese specifications, here is why this specific batch is highly sought after by precision stamping factories:
- Delivery Condition: Annealed & Skin-passed. This critical process eliminates yield point elongation (stretcher strains), guaranteeing a perfectly flat surface and zero "orange peel" defects during your deep drawing process.
- Exceptional Elongation: 34%. Standard SPA-C requires basic formability, but an elongation of 34% means this steel possesses ultimate ductility. You can perform complex 90-degree bending, roll-forming, and deep stamping with zero risk of cracking.
- High Yield Strength: 377 MPa . Far exceeding the standard ≥315 MPa requirement, ensuring excellent structural integrity for lightweight corrugated roofing and architectural facades.
- Surface Finish: Matte/Dull. The ideal surface roughness to accelerate the formation of a uniform, aesthetic rust patina when exposed outdoors.
Authentic Mill Test Certificate (MTC) for SPA-C Cold Rolled Weathering Steel Coil, showing Annealed and Skin-passed condition.
📩 Download Full PDF MTC Sample / Request a Quote]
Need a specific thickness for your SPA-C project? Contact our engineering team today to get the latest inventory list and request a high-resolution MTC sample for your structural engineer's approval!
JIS SPA-C corten weathering steel plate chemical composition
| Grade | C ≤ | Si | Mn | P | S ≤ | Cu | Cr | Ni ≤ |
| SPA-C | 0.12 | 0.25~0.75 | 0.20~0.50 | 0.070~0.150 | 0.040 | 0.25~0.60 | 0.30~1.25 | 0.65 |
JIS SPA-C corten steel sheet metal mechanical property
| Grade |
Elastic modulus |
190 - 210 GPa at 20 °C |
|
JIS G3125 Grade SPA-C |
Elongation A5 |
26 % at 20 °C |
|
Poisson's ratio |
0.3 [-] at 20 °C |
|
|
Tensile strength |
450 MPa at 20 °C |
|
|
Yield strength |
315 MPa at 20 °C |
Why Choose Our SPA-C Cold Rolled Steel? (Core Advantages)
When manufacturing intricate architectural components or precision stamped parts, material formability and surface finish are everything. Here is why our SPA-C coils stand out:
Annealed & Skin-Passed Delivery: Unlike raw full-hard coils that easily crack or show "orange peel" defects during fabrication, our SPA-C is strictly annealed and skin-passed (temper rolled). This critical process eliminates yield point elongation (stretcher strains), guaranteeing a perfectly flat and flawless surface.
Ultimate Formability: With a slightly lower minimum yield strength (≥ 315 MPa) but dramatically higher ductility, SPA-C can undergo complex 90-degree bending, roll-forming, and deep stamping with zero risk of cracking.
Faster, More Uniform Rusting: Because it is cold-rolled, SPA-C is completely free from the dark, rough mill scale found on hot-rolled steel. When exposed to the atmosphere, it develops a rich, orange-brown protective oxide layer (patina) much faster and far more evenly, making it the favorite choice of high-end architects.
Primary Applications for SPA-C
Because of its thin gauge and flawless surface, SPA-C cannot be replaced by hot-rolled SPA-H in precision industries. It is highly specified for:
Architectural Facades & Cladding: Decorative wall panels, perforated privacy screens, and indoor/outdoor art installations.
Lightweight Roofing: Corrugated weathering steel roofing sheets that require complex roll-forming.
HVAC & Environmental Systems: Exhaust ducts, industrial chimney linings, and air preheater components.
Urban Furniture & Planters: High-end landscape planters, retaining walls, and signage.
GNEE STEEL's Custom Processing Services
It is often hard to find SPA-C in small batches, as large steel mills typically demand a 50-ton Minimum Order Quantity (MOQ). At GNEE STEEL, we bridge that gap.
Our advanced in-house CNC processing center offers:
Precision Slitting & Cut-to-Length: We can supply custom-width strips or perfectly flat sheets to match your exact Bill of Materials (BOM).
CNC Laser Cutting (Hollow Carving): Send us your CAD/DWG files, and we will cut intricate patterns with ±1mm tolerance.
Accelerated Pre-Weathering & Rust Sealing: Don't want to wait 6 months for nature to rust your steel? We offer eco-friendly chemical pre-rusting and transparent surface curing (rust sealing) to guarantee zero red rust runoff onto your concrete or marble walls!
Frequently Asked Questions (Buyer FAQs)
Q1: What is the delivery condition of your SPA-C steel?
Answer: All our SPA-C cold-rolled weathering steel is delivered strictly in the Annealed and Skin-passed (Temper Rolled) condition. This eliminates stretcher strains and guarantees an exceptionally smooth surface and superior mechanical properties for your precision fabrication.
Q2: Will SPA-C crack during 90-degree bending or deep drawing?
Answer: No. SPA-C is specifically engineered for excellent formability. As shown in our MTCs, our SPA-C often achieves an elongation rate of over 30%, making it the perfect material for complex stamping, roll-forming, and sharp-angle bending without any risk of cracking.
Q3: Can I substitute SPA-C with SPA-H to save costs?
Answer: We strongly advise against this for precision projects. SPA-H is hot-rolled, supplied in thicker gauges (1.6mm+), and has a rougher mill scale surface. If you are manufacturing thin, lightweight architectural panels or precision stamped parts (e.g., 0.8mm or 1.2mm), hot-rolled SPA-H cannot achieve the required dimensional tolerances or the smooth aesthetic finish of SPA-C.
Q4: What is your MOQ for SPA-C? It is hard to find in small batches.
Answer: We understand that high-end architectural and stamping projects often require flexible material quantities. Through our processing center, we provide custom slitting and shearing services, allowing us to support smaller batch orders and LCL (Less than Container Load) shipments to perfectly match your project needs.
GNEE group team photo
GNEE group customer visit
GNEE Group participates in foreign steel exhibitions
We have excellent after-sales service. If you have any questions about JIS G3125 Grade SPA-C Weathering Steel Plate, you can contact us and we will reply to you within two hours.
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