SS490 is a high strength low alloy steel plate, conforming to the Japanese Industrial Standard JIS G3101. Its key characteristic is a minimum tensile strength of 490 MPa.
By carefully controlling the carbon equivalent (Ceq), it achieves higher strength than mild steel while maintaining superior weldability, often reducing the need for complex pre-heating or post-weld treatments.
| Property | Typical Value |
| Tensile Strength | 490 – 610 MPa |
| Yield Strength | ≥ 325 MPa (thickness-dependent) |
| Elongation | ≥ 17% (on 200mm gauge length) |
| Carbon Equivalent | Typically ≤ ~0.40% |
| Main Alloying Elements | C, Mn, Si, Nb/V |
To help you position SS490 in the broader material selection spectrum, here is a direct comparison with its closest siblings within the JIS standard and a key American equivalent.
| Grade | Standard | Key Properties |
| SS400 | JIS G3101
|
Yield Strength: ~245 MPa
Tensile Strength: 400-510 MPa Carbon Equivalent: Very Low Key Point: Lowest strength but offers excellent formability and weldability. |
| SS490 | Yield Strength: ≥325 MPa
Tensile Strength: 490-610 MPa Carbon Equivalent: Controlled (~≤0.40%) Key Point: Significantly stronger than SS400 while maintaining excellent weldability. |
|
| SS540 | Yield Strength: ≥400 MPa
Tensile Strength: 540-655 MPa Carbon Equivalent: Higher Key Point: Higher strength, but often with a higher carbon equivalent, requiring stricter welding procedures (e.g., pre-heating). |
|
| ASTM A572 Gr.50 | ASTM A572 | Yield Strength: 345 MPa
Tensile Strength: 450 MPa Min. Carbon Equivalent: Similar to SS490 Key Point: The most common HSLA steel in the US system. Performance is highly similar to SS490/Q355B. |
Factory steel frames, warehouse trusses, and auxiliary components for medium-span bridges.
Crane booms, excavator undercarriages, and support structures for concrete pump trucks—areas requiring good weldability and dependable strength.
Trailer longitudinal beams, truck sub-frames, and bus chassis.
Heavy-duty industrial shelving, agricultural machinery frames, and various custom fabrications.
The following represents our standard stocking and production range. Custom dimensions outside this range can be evaluated upon inquiry.
| Item | Typical Range / Specification |
| Thickness | 6 mm — 200 mm |
| Width | 1500 mm — 3000 mm |
| Length | 6000 mm — 12000 mm |
| Form | As-rolled plates, or Pre-cut to size |
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