SM490 steel is a cornerstone material in the global construction and engineering sectors. As a standardized hot-rolled steel under the JIS G3106 specification, it is specifically engineered for welded structures that require superior strength without sacrificing weldability. Whether you are designing bridges, ships, or high-rise buildings, understanding the technical nuances of this grade is vital for structural integrity.
Technical Specifications and Grade Variants
The “SM” designation stands for “Steel Marine,” though its application extends far beyond shipbuilding. Within the SM490 category, several sub-grades exist—such as SM490A, SM490B, and SM490C—differing primarily in their impact test requirements. For instance, SM490C is often preferred for colder environments where low-temperature toughness is a critical safety factor.
Chemical Composition of SM490 Steel
The reliability of SM490 steel stems from its precise chemical balance. By controlling carbon and manganese levels, manufacturers ensure the material remains easy to weld while maintaining high tensile strength.
| Grade | C (max) | Si (max) | Mn (max) | P (max) | S (max) |
| SM490A | 0.20% | 0.55% | 1.60% | 0.035% | 0.035% |
| SM490B | 0.18% | 0.55% | 1.60% | 0.035% | 0.035% |
Mechanical Properties
The mechanical performance of this grade is what truly sets it apart from lower-carbon alternatives like SS400. It offers a significant jump in yield point, allowing engineers to reduce the overall weight of a structure by using thinner plates.
| Property | Value (Thickness ≤ 16mm) |
| Yield Strength | Min 325 MPa |
| Tensile Strength | 490 – 610 MPa |
| Elongation | Min 22% |
Applications of SM490 Steel
Due to its robust nature, SM490 steel is frequently utilized in heavy-duty machinery and large-scale infrastructure. Its excellent fatigue resistance makes it the preferred choice for high-performance steel structures.
If you are looking for reliable sourcing and customized cutting services, HNS Metal provides premium JIS G3106 compliant plates tailored to your project’s specific tolerances. Choosing the right structural steel ensures longevity and safety in even the most demanding environments.
