Products Description
SPA-C steel weathering plate is the atmospheric corrosion resistance steel. The C of SPA-C means cold-rolled. SPA-C plate is cold-rolled steel plate that the thickness of plate is 0.6mm-2.3mm. The strength of SPA-C is less than SPA-H.
SPA-H Weathering steel all made of carbon steel and copper, nickel, phosphorus and other chemical elements. The content of these chemical elements, only a few percent. Because different alloying elements, weather resisting steel has better mechanical properties, as well as greater corrosion resistance.
chemical composition
SPA-C steel
|
Grade |
C |
Mn |
P |
S |
Si |
Ni |
Cr |
Cu |
|
SPA-C |
≤0.12 |
≤0.6 |
0.007-0.15 |
≤0.035 |
0.25-0.75 |
≤0.65 |
0.30-1.25 |
0.25-0.55 |
SPA-H steel
| Element (Symbol and Name) | Percentage Range (%) |
|---|---|
| C (Carbon) | 0.12 - 0.20 |
| Mn (Manganese) | 0.50 - 1.50 |
| P (Phosphorus) | ≤ 0.04 |
| S (Sulfur) | ≤ 0.03 |
| Cu (Copper) | 0.25 - 0.55 |
| Cr (Chromium) | 0.20 - 0.50 |
| Ni (Nickel) | 0.30 - 0.50 |
mechanical properties
SPA-C steel
|
Grade |
Yield strength |
Tensile strength |
Elongation |
|
SPA-C |
≥315MPa |
≥450MPa |
26% |
SPA-h steel
| Property | Condition/Temper | Test Temperature | Typical Value/Range (Metric) | Typical Value/Range (Imperial) | Reference Standard for Test Method |
|---|---|---|---|---|---|
| Tensile Strength | As Rolled | Room Temp | 490 - 620 MPa | 71 - 90 ksi | ASTM E8 |
| Yield Strength (0.2% offset) | As Rolled | Room Temp | 355 - 450 MPa | 51 - 65 ksi | ASTM E8 |
| Elongation | As Rolled | Room Temp | 20 - 25% | 20 - 25% | ASTM E8 |
| Hardness (Brinell) | As Rolled | Room Temp | 150 - 200 HB | 150 - 200 HB | ASTM E10 |
| Impact Strength (Charpy) | -40°C | -40°C | 27 J | 20 ft-lbf | ASTM E23 |
The difference between SPA-C weathering steel and SPA-H weathering plate
In the JIS G 3125 standard, both SPA-H and SPA-C belong to the family of weathering steels, but they differ in terms of performance and applications. SPA-H is defined as a high-strength weathering steel, with a typical yield strength above 355 MPa and tensile strength ranging from 490–630 MPa. This makes it suitable for structural applications that must withstand complex loads and long-term exposure to harsh environments. SPA-C, on the other hand, has a yield strength in the range of 245–355 MPa. Its performance is comparatively moderate, with a greater emphasis on weldability and workability.
In terms of chemical composition, SPA-H contains higher amounts of alloying elements, especially copper, phosphorus, chromium, and nickel. These elements allow SPA-H to form a more stable protective layer under atmospheric conditions, thereby providing stronger weather resistance. SPA-C, by comparison, contains relatively fewer alloying additions. While it still offers good weathering properties, its main advantage lies in better formability, making it more suitable for lighter structural applications.
When it comes to applications, the difference between the two becomes even clearer. SPA-H is widely used in bridges, highway guardrails, containers, vehicles, and construction machinery-fields where high strength and long-term durability are critical. Its advantage lies in significantly reducing maintenance costs while ensuring structural stability in harsh climates. SPA-C, meanwhile, is often used for building facades, exterior cladding, landscaping structures, and urban public art installations. These applications do not demand very high strength but place great value on appearance and corrosion resistance.
SPA-H can be seen as the "structural backbone" among weathering steels, designed for engineering and heavy-duty structures, while SPA-C is more of the "artistic" option, widely used in architecture and landscaping. The former emphasizes strength and durability, while the latter highlights flexibility in processing and aesthetic appeal. Together, both grades play complementary roles in modern construction and engineering industries.
