The steel grade ​S355J0H​ is a ​hot-finished hollow section​ structural steel specified in the European standard ​EN 10210​. Its key mechanical properties, as defined by the standard for delivery conditions, are summarized below:

Key Mechanical Properties (Minimum Guaranteed Values)

​Yield Strength (ReH / Rp0.2):​

Thickness (t) ≤ 16 mm: ​355 MPa​ (N/mm²)

16 mm < t ≤ 40 mm: ​345 MPa​

40 mm < t ≤ 63 mm: ​335 MPa​

63 mm < t ≤ 80 mm: ​325 MPa​

t > 80 mm ≤ 100 mm: ​315 MPa​

​Tensile Strength (Rm):​

​470 MPa​ to ​630 MPa​

​Elongation (A):​

Minimum percentage elongation varies slightly with thickness:

Thickness ≤ 40 mm: ​22%​ (based on 5.65√S₀ gauge length)

Thickness > 40 mm: ​20%​ (based on 5.65√S₀ gauge length)

​Impact Toughness (KV):​

​Sub-Zero Toughness:​ The "J0" designation indicates minimum ​Charpy V-notch impact energy​ at ​-20°C​.

​Hardness:​

Typically not a primary specified requirement for structural grades like this, but Brinell hardness values would generally be in the range of ​HB 130 - 170​.

Essential Context

​Standard:​ EN 10210-1: Hot finished structural hollow sections of non-alloy and fine grain steels - Part 1: Technical delivery conditions.

​Steel Type:​ Non-alloy fine grain structural steel.

​Manufacturing Process:​ Hot finished seamless or welded hollow sections, followed by thermomechanical rolling (​TMCP​), denoted by the ​'H'​ suffix. This process enhances strength and toughness while allowing leaner chemical compositions.

​Delivery Condition:​ As-rolled (+AR) or normalized rolled (+N) condition. Impact properties are specified in the delivery condition.

​Welding:​ Good weldability is a typical characteristic of S355 steels, though specific procedures should be followed based on application codes (e.g., EN 1993-1-8, AWS D1.1).

Typical Applications

Heavy construction (buildings, bridges)

Offshore structures

Crane girders and booms

Heavy-duty support structures

Agricultural machinery frames

Material handling equipment

Parts requiring higher toughness at sub-zero temperatures (due to the 'J0' rating).

​Important Note:​ For use in critical structural applications, always refer to the ​official material test certificate (MTC)​ supplied with the specific batch of steel. This certificate provides the actual test results for the properties guaranteed by the standard. Design calculations should use the specified minimum values from the relevant design standard (e.g., EN 1993).