SPA-H SPA-C Corten Weathering Steel

SPA-H SPA-C Corten Weathering Steel

Both SPA-H and SPA-C are superior atmospheric corrosion-resisting steels specified under the Japanese standard JIS G 3125 (often referred to as Corten equivalents). The fundamental difference lies in their rolling processes: the "H" stands for Hot-Rolled, designed for thicker, heavy-duty structural applications (like shipping containers); while the "C" stands for Cold-Rolled, designed for thinner, high-precision, and lightweight applications (like roofing and stamped parts).

 

High strength weathering steel is widely used in air preheater, coal economiser, railway vehicles, container manufacturing, bridge building and construction. Hot Rolled, Cold Rolled, Hot Rolled, Cold Rolled, Cold Rolled, TMCP, T/QT are available on request.

 

SPA-H SPA-C Corten Weathering Steel Mill Test Certificate

 

Authentic EN 10204 3.1 Mill Test Certificate (MTC) for Our SPA-H Steel Coils

We source our SPA-H weathering steel exclusively from top-tier Chinese state-owned mills like Shougang Group, ensuring premium and stable quality for your projects.

 

As shown in the authentic MTC above, our recent batch of 10mm SPA-H hot-rolled coils far exceeds the JIS G 3125 standard requirements:

 

• Superior Yield Strength: Tested at 424 MPa (Standard requires ≥ 345 MPa), providing exceptional structural safety for heavy-duty shipping containers and bridges.
• Excellent Toughness: High impact energy absorption (Avg. 178 Joules at 20°C), preventing brittle fracture during fabrication.
• Strict Chemical Control: Optimal levels of Cu, Cr, and P guarantee the rapid formation of a dense, weather-resistant patina.

 

Every order from GNEE STEEL is delivered with a fully traceable, original 3.1 Inspection Certificate. You get exactly what you pay for-100% prime quality.

Product: Cold Rolled Weathering Steel Strip

Grade: SPA-C (JIS G 3125)

Delivery Condition: Annealed + Skin-passed

SPA-C Cold Rolled Weathering Steel Strip (Annealed & Skin-passed)
We supply premium SPA-C cold-rolled weathering steel strips. Delivered in an annealed and skin-passed condition, our steel strips guarantee excellent surface flatness, superior formability, and the elimination of stretcher strains. This makes them highly ideal for precision stamping, roll-forming, and manufacturing lightweight architectural components or HVAC exhaust ducts.

 

Regarding your inquiry, we can provide the SPA-C Cold Rolled Steel Strip. The delivery condition will be strictly Annealed and Skin-passed, ensuring the best surface quality and mechanical properties for your further cold forming and stamping processes."

 

Grade	C	Si	Mn	P	S	Cr	Cu	V	Ni
SPA-H	0.12	0.20-0.75	0.60	0.07-0.15	0.035	0.30-1.25	0.25-0.50	-	0.65

 

 

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

 

 

Grade	Minimumyield point (ReH Mpa *)	Tensile strengthRm MPa	Minimumelongation A(Lo=5.65 ?So) %
SPA-H	355	490	22

 

 

Grade	Yield strength	Tensile strength	elongation
SPA-C	≥ 325 MPa	≥ 450 MPa	≥ 26

 

SPA-C corten weathering steel plate equivalent grades

The equivalent grades of SPA-C corten weathering steel plate include HW350, SPA-H JIS G3125, ASTM A242 (COR-TEN A), ASTM A588 (COR-TEN B), S355J2WP+N, S355J2W+N, S355JOWP, S355JOW, S355J2W, 1.8946, 1.8965, SAILCOR IRSM41-97.

 

 

1. The Core Differences: Manufacturing & Applications

Although they share almost identical chemical compositions rich in Copper (Cu), Chromium (Cr), and Phosphorus (P) to create the famous rust patina, their physical forms are completely different.

 

• SPA-H (Hot-Rolled Weathering Steel):

Manufactured at high temperatures, SPA-H comes with a rougher surface (mill scale) and is supplied in heavier thicknesses (typically 1.6mm to 12.0mm+). It is the undisputed global standard for manufacturing ISO shipping containers, railway wagons, and heavy architectural structures.

 

• SPA-C (Cold-Rolled Weathering Steel):

Processed further at room temperature, SPA-C offers a highly refined, smooth surface finish with extremely tight thickness tolerances. It is supplied in much thinner sheets (typically 0.6mm to 1.5mm). It is highly favored for lightweight corrugated roofing, HVAC exhaust ducts, precision decorative facades, and stamped parts.

 

2. What Buyers Must Compare When Sourcing (The Buyer's Checklist)

When a purchasing manager or engineer is deciding between SPA-H and SPA-C, they must evaluate the following three critical factors:

 

🔍 Factor 1: Required Thickness (The Dealbreaker)

• If your project requires steel plates thicker than 1.6mm (e.g., 2.0mm, 3.0mm, 6.0mm), you must purchase SPA-H.
• If your project involves thin-gauge sheet metal below 1.5mm (e.g., 0.8mm, 1.0mm, 1.2mm), you must purchase SPA-C.

 

🔍 Factor 2: Yield Strength & Load Bearing

• SPA-H provides a higher minimum yield strength of 345 MPa, making it suitable for load-bearing structures that must withstand heavy cargo and impact.
• SPA-C has a slightly lower minimum yield strength of 315 MPa, prioritizing excellent ductility, deep drawing, and formability over brute strength.

 

🔍 Factor 3: Surface Finish & Formability

If you are running an automated stamping line to produce intricate shapes without cracking, SPA-C provides the necessary cold-forming precision and smooth surface.

If you are laser-cutting and welding large frames where minor surface roughness is acceptable, SPA-H is the most cost-effective choice.

 

3. The Big Question: Can SPA-H and SPA-C Substitute Each Other?

The Short Answer: NO. In 95% of engineering scenarios, they cannot and should not be substituted for one another.

 

The Technical Explanation:
Substitution between grades usually happens when materials share the same thickness and mechanical properties but belong to different national standards (e.g., swapping SPA-H with European S355J0WP).

However, SPA-H and SPA-C are designed for completely different dimensional ranges and processing methods.

You cannot substitute 3.0mm SPA-H with SPA-C, because cold-rolled mills generally do not produce 3.0mm thick weathering coils.

Conversely, you cannot substitute 0.8mm SPA-C with SPA-H, because hot-rolling mills cannot achieve the ultra-thin, precise tolerances and smooth surface required for 0.8mm architectural profiles.

 

Expert Advice: Never alter the "H" or "C" designation on your Bill of Materials (BOM) without consulting your structural engineer. If you face a stock shortage, look for cross-standard equivalents (e.g., replacing SPA-H with Chinese Q355GNH), rather than switching between hot-rolled and cold-rolled grades.

 

4. Head-to-Head Technical Comparison Table

Feature	SPA-H (JIS G 3125)	SPA-C (JIS G 3125)
Rolling Process	Hot Rolled	Cold Rolled
Typical Thickness	1.6 mm – 12.0 mm+	0.6 mm – 1.5 mm
Min. Yield Strength	≥ 345 MPa	≥ 315 MPa
Min. Tensile Strength	≥ 490 MPa	≥ 450 MPa
Surface Condition	Rougher (Mill Scale)	Smooth & Highly Precise
Formability	Good (Bending, Welding)	Excellent (Stamping, Deep Drawing)
Primary Industry	Shipping Containers, Railways, Bridges	Roofing, Ducts, Precision Facades

 

Need Fast Delivery for SPA-H or SPA-C?

Whether you are manufacturing heavy-duty shipping containers or intricate architectural roofing, GNEE STEEL maintains massive ready stocks of both SPA-H coils and SPA-C sheets. We provide precision slitting, cut-to-length, and CNC profiling services to meet your exact specifications.

[📩 Contact our experts today for the latest price and stock list!]

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Q1: What is your negative thickness tolerance for SPA-H coils/plates?
Answer: For heavy-duty applications like shipping containers and railway wagons, we know that precise thickness is critical to balancing structural strength and vehicle dead weight. We utilize advanced hot-rolling technology to strictly control the negative tolerance (typically within -0.1mm, or customized to your requirements). This ensures your automated production lines run smoothly while optimizing your overall material costs.

 

Q2: Can SPA-H be used as a direct equivalent to Corten A or S355J0WP?
Answer: Yes, absolutely. In practical engineering, SPA-H is widely recognized as the most cost-effective Asian equivalent to the US Corten A and European S355J0WP. It shares the same high-phosphorus chemical composition (enriched with Cu and Cr) and offers a highly overlapping minimum yield strength of 345 MPa. We provide a fully traceable EN 10204 3.1 Mill Test Certificate (MTC) for your engineering team's approval before shipment.

 

Q3: Are your SPA-H coils supplied with a mill edge or a slit edge?
Answer: We offer flexible supply options based on your fabrication setup. If you run automated uncoiling and roll-forming lines (such as corrugated container panel manufacturing), we highly recommend our Slit Edge coils. They provide exact width precision, saving you secondary trimming costs and minimizing material waste. Standard Mill Edge is also available for general structural fabrication.

 

Q4: Do you have ready stock for common thicknesses like 1.6mm and 2.0mm?
Answer: Yes! We understand that container repair and urgent manufacturing projects cannot wait for a 45-day mill rolling schedule. GNEE STEEL maintains massive ready stocks of SPA-H coils in popular thicknesses (1.6mm, 2.0mm, 3.0mm, up to 12.0mm) at major Chinese ports, ready to be cut-to-length or shipped immediately.

 

 

Q1: What is the delivery condition of your SPA-C steel? Is it annealed and skin-passed?
Answer: Yes. Unlike raw full-hard coils that are prone to cracking, all our SPA-C cold-rolled weathering steel is delivered strictly in the Annealed and Skin-passed (Temper Rolled) condition. This premium manufacturing process eliminates yield point elongation (stretcher strains), guaranteeing 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, it will not. SPA-C is specifically engineered for excellent formability. Its minimum yield strength is slightly lower (315 MPa) compared to its hot-rolled counterpart (SPA-H), which gives it far superior ductility and elongation. This makes SPA-C the perfect material for complex stamping, roll-forming, and sharp-angle bending, such as lightweight corrugated roofing and HVAC exhaust ducts.

 

Q3: Does SPA-C rust faster and more uniformly than SPA-H?
Answer: Yes! Because SPA-C is a cold-rolled product, its surface is highly refined and entirely free from the dark, rough mill scale found on hot-rolled steel. When exposed to outdoor environments, SPA-C develops its protective, highly aesthetic orange-brown rust patina much faster and far more uniformly. This makes it the absolute favorite among architects for high-end decorative facades and indoor/outdoor art installations.

 

Q4: It is hard to find SPA-C in small batches. What is your MOQ?
Answer: We understand that high-end architectural and precision stamping projects often require smaller material quantities, and large steel mills typically demand a 50-ton Minimum Order Quantity (MOQ). At GNEE STEEL, we offer flexible solutions. Through our in-house processing center, we provide custom slitting and cut-to-length services, allowing us to support smaller batch orders to perfectly match your project's Bill of Materials (BOM).

 

 

 

 

We have excellent after-sales service. If you have any questions about SPA-H SPA-C Corten Weathering Steel, you can contact us and we will reply to you within two hours.

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