SM490B steel plate is a JIS G3106 carbon structural steel widely used for welded structures where good strength, weldability, and structural reliability are required.
It is commonly used in bridge structures, ships and marine structures, industrial equipment, storage tanks, vehicles, and other welded structural components. Its combination of strength and fabrication performance makes SM490B a practical choice for medium- and heavy-duty structural applications.
SM490B has a tensile strength of 490–610 MPa, while its minimum yield strength varies from 275 to 325 MPa depending on plate thickness.
What is SM490B steel?
SM490B is a structural steel grade specified under JIS G3106 for welded structures. The grade is designed to provide a balance of yield strength, tensile strength, weldability, and structural performance. Compared with general-purpose mild structural steels, SM490B is commonly selected for welded components that require higher strength and reliable fabrication performance.
Gnee Steel offers hot-rolled SM490B steel plates with thicknesses from 6 mm to 400 mm, widths from 1,500 mm to 4,000 mm, and lengths from 5,000 mm to 16,000 mm, subject to production and project requirements.
For smaller or customized sizes, we can cut the plates to the required dimensions from larger base plates in our processing plant. Shot blasting and painting are also available, including surface preparation to Sa 2.5 according to ISO 8501-1.
For project-based orders, Gnee Steel can provide relevant material documentation, including mill test certificates and inspection records, subject to the order requirements. Chemical composition and mechanical properties can be verified against the applicable JIS G3106 requirements.
Mechnical property for SM490B steel plate
| Thickness | Yield Strength (Min.) | Tensile Strength |
|---|---|---|
| ≤ 16 mm | 325 MPa | 490–610 MPa |
| > 16–40 mm | 315 MPa | 490–610 MPa |
| > 40–75 mm | 295 MPa | 490–610 MPa |
| > 75–100 mm | 295 MPa | 490–610 MPa |
| > 100–160 mm | 285 MPa | 490–610 MPa |
| > 160 mm | 275 MPa | 490–610 MPa |
According to the thickness range, the minimum yield strength of SM490B decreases from 325 MPa for plates up to 16 mm thick to 275 MPa for plates over 160 mm, while the tensile strength remains within the specified 490–610 MPa range.
Chemical Composition of SM490B Steel Plate – Ladle Analysis, Maximum %
| Main chemical elements composition of SM490B steel plate | |||||
| Thickness(mm) | C | Si | Mn | P | S |
| T≤50 | 0.18 | 0.55 | 1.60 | 0.035 | 0.035 |
| 50 | 0.20 | ||||
SM490B Welding and Fabrication
SM490B is designed for structural applications involving welding and fabrication. However, welding procedures should be selected according to plate thickness, joint design, welding method, heat input, and project requirements.
For thicker plates or demanding welded structures, appropriate preheating, interpass temperature control, and qualified welding procedures may be required. Fabrication should follow the applicable project specification and qualified welding procedure.
FAQ
What is SM490B steel?
SM490B is a JIS G3106 structural steel grade used for welded structures. It provides a combination of strength, weldability, and structural reliability for applications such as bridges, ships, industrial structures, and other fabricated components.
What is the tensile strength of SM490B?
The tensile strength of SM490B is 490–610 MPa according to the applicable JIS G3106 requirements, while the minimum yield strength varies according to plate thickness.
What is SM490B used for?
SM490B is commonly used for welded bridges, ships and marine structures, vehicles, industrial equipment, storage tanks, and other structural components requiring reliable strength and fabrication performance.
Is SM490B weldable?
Yes. SM490B is intended for welded structural applications. However, the welding procedure should be selected according to plate thickness, joint design, welding method, heat input, and applicable project requirements.
Can SM490B steel plates be cut and processed?
Yes. SM490B plates can be cut to required dimensions, and additional processing such as shot blasting and painting can be arranged according to project requirements.