When sourcing structural carbon steel plates, SS400 and ASTM A36 are two of the most commonly compared grades. Both materials are mild carbon steels widely used in construction, machinery, and manufacturing. They share similar strength levels and mechanical properties - but differ in standards, chemical composition, and specific applications.
Understanding the differences between SS400 (Japan) and A36 (USA) is crucial for choosing the right material for your project, ensuring performance, compliance, and cost efficiency.
1. Standards and Origin
| Grade | Standard | Country / Region | Specification Type |
|---|---|---|---|
| SS400 | JIS G3101 | Japan | Hot Rolled Carbon Steel Plate for General Structure |
| ASTM A36 | ASTM A36 / A36M | United States | Carbon Structural Steel Plate for Construction |
2. Chemical Composition Comparison
| Element | SS400 (JIS G3101) | ASTM A36 |
|---|---|---|
| Carbon (C) | ≤ 0.23% | ≤ 0.26% |
| Manganese (Mn) | ≤ 1.60% | 0.60–0.90% |
| Silicon (Si) | ≤ 0.50% | ≤ 0.40% |
| Phosphorus (P) | ≤ 0.050% | ≤ 0.040% |
| Sulfur (S) | ≤ 0.050% | ≤ 0.050% |
| Iron (Fe) | Balance | Balance |
Key Difference:A36 typically allows slightly higher manganese and carbon content, which provides slightly better strength but reduces ductility compared to SS400.
3. Mechanical Properties Comparison
| Property | SS400 | ASTM A36 |
|---|---|---|
| Tensile Strength (MPa) | 400 – 510 | 400 – 550 |
| Yield Strength (MPa) | ≥ 245 | ≥ 250 |
| Elongation (%) | ≥ 23 | ≥ 20 |
| Hardness (HBW) | ≤ 160 | ≤ 200 |
| Density (g/cm³) | 7.85 | 7.85 |
SS400 vs. ASTM A36 Carbon Steel Plate
| Parameter | SS400 | ASTM A36 |
|---|---|---|
| Standard | JIS G3101 | ASTM A36/A36M |
| Thickness Range | 2 – 200 mm | 2 – 200 mm |
| Width | 1000 – 3000 mm | 1000 – 3000 mm |
| Length | 2000 – 12000 mm | 2000 – 12000 mm |
| Surface Finish | Hot Rolled, Pickled, Oiled | Hot Rolled, Pickled, Oiled |
| Delivery Condition | As Rolled / Normalized | As Rolled / Normalized |
| Applications | Construction, machinery, shipbuilding | Bridges, oil rigs, heavy structures |
5. Applications
Both SS400 and A36 carbon steel plates are used for structural and fabrication purposes, including:
Building frames and bridges
Machinery base plates and supports
Ship hulls and deck plates
Boiler and tank fabrication
Automotive and trailer frames
Pressure vessels (non-critical)
SS400 vs. A36: Which One Should You Choose?
| Scenario | Recommended Grade | Reason |
|---|---|---|
| General construction | SS400 | Affordable and easily available |
| Export to USA / ASTM projects | A36 | Required by ASTM certification |
| Higher load-bearing or welding structures | A36 | Slightly stronger tensile properties |
| Fabrication and bending work | SS400 | Better ductility and forming behavior |
| Cost-sensitive applications | SS400 | Lower nickel and alloy content, cheaper |
Why choose Gnee as your SS400 carbon steel plate supplier?
We have over 18 years of global experience exporting structural and carbon steel, offering factory-direct pricing and rigorous quality control certified by ISO, SGS, and BV. We maintain a large inventory of SS400, A36, and S235JR steel plates and offer comprehensive fabrication services including cutting, drilling, bending, and CNC machining. We offer flexible customization of sizes, thicknesses, and finishes, and ship worldwide with fast delivery within 7-15 days.
Packaging and Delivery
| Item | Details |
|---|---|
| Package | Standard export seaworthy package: waterproof wrapping, edge protection, wooden pallets or boxes. |
| Marking | Grade, heat number, size, and manufacturer's logo printed or stamped on each plate. |
| Loading Port | Tianjin, Qingdao, or Shanghai Port, China. |
| Container Capacity | 1 × 20ft container: Max. 25 Tons, Max. length 5.8m 1 × 40ft container: Max. 25 Tons, Max. length 11.8m |
| Delivery Time | 7–15 working days after receiving advance payment, depending on order quantity. |
