What Is S460M Steel?
S460M is a thermo-mechanically rolled, fine-grain high-strength structural steel specified in EN 10025-4. It provides a minimum yield strength of 460 MPa, excellent toughness, ductility, and weldability, and good plate flatness and formability. The grade is commonly used in bridges, offshore structures, cranes, heavy machinery, and structural steel frameworks, where the high strength-to-weight ratio supports lighter and more efficient designs.
What Does the M Stand For?
In S460M, the M stands for thermo-mechanically rolled. Thermo-mechanical rolling, also known as TMCP, is a controlled rolling and cooling process that refines the grain structure of the steel. This process enhances toughness, strength, and ductility, especially in thicker plates, compared with normalized or standard rolled steels. As a result, S460M combines high yield strength of 460 MPa with excellent low-temperature toughness and weldability.
Chemical Composition
Typical composition values in percent by weight for S460M are: carbon 0.22 max, silicon 0.55 max, manganese 1.00-1.60, phosphorus 0.025 max, and sulfur 0.020 max, with micro-alloying elements niobium up to 0.06%, vanadium up to 0.12%, and titanium up to 0.03%. The low impurity levels and the fine-grain practice support the toughness and weldability of the grade; thickness-dependent limits should be confirmed against EN 10025-4.
Mechanical Properties
Typical mechanical values are: minimum yield strength of 460 MPa for plate up to 16 mm and 440-460 MPa for plate from 40 mm to 100 mm; tensile strength of 540-720 MPa; elongation of at least 20-22%; and a Charpy V-notch impact test at -20 °C for the M toughness class, while the ML class is tested at -50 °C for colder applications. Confirm the required impact energy and thickness-dependent values against EN 10025-4 and the mill test certificate. Density is 7.85 g/cm³.
Applications and Selection Notes
S460M is ideal for bridges, offshore structures, cranes, and heavy engineering applications. When sourcing the material, ensure that the delivery condition and certification comply with EN 10025-4 and request mill test certificates, verify plate size and thickness availability for the project, and confirm the low-temperature toughness requirements: standard S460M guarantees -20 °C, while S460ML is intended for colder applications. Testing and inspection should meet the project standards, especially for critical structures.
Frequently Asked Questions
What is S460M steel? S460M is a thermo-mechanically rolled, fine-grain high-strength structural steel specified in EN 10025-4 with a minimum yield strength of 460 MPa.
What does the M in S460M mean? M stands for thermo-mechanically rolled, a controlled rolling and cooling process that refines the grain structure and improves toughness, strength, and ductility in thicker plates.
What are the mechanical properties of S460M? Minimum yield 460 MPa for plate up to 16 mm, tensile 540-720 MPa, elongation at least 20-22%, and Charpy impact testing at -20 °C for the M class.
What is the difference between S460M and S460ML? S460M is impact-tested at -20 °C, while S460ML is tested at -50 °C, making S460ML the choice for colder applications.
Where is S460M used? It is used in bridges, offshore structures, cranes, heavy machinery, and structural steel frameworks.
Is S460M easy to weld? Yes. The fine-grain structure and controlled composition give excellent weldability with conventional processes, and the required testing and inspection should follow the project specification.
