While S275JR is a versatile steel, its use is subject to important limitations based on its specified properties:
Temperature Limitations:
Low-Temperature Service: It is not suitable for low-temperature applications without careful assessment. Its guaranteed impact toughness is only at +20°C. For structures operating consistently below 0°C, or where low-temperature brittleness is a concern, grades like S275J0 (0°C test) or S275J2 (-20°C test) must be specified.
High-Temperature Service: It is not a creep-resistant steel. Its strength decreases significantly at elevated temperatures (e.g., above 300-400°C). For fire resistance, it must be protected by fireproofing materials (boards, sprays, intumescent paint) as per building codes.
Corrosion Resistance: S275JR has no inherent atmospheric corrosion resistance beyond the temporary protection of mill scale. In exposed or corrosive environments (coastal, industrial), it requires a protective coating system (paint, galvanizing) or must be replaced by a weathering steel grade (e.g., S355J2WP).
Fatigue and Dynamic Loading: For structures subjected to high-cycle fatigue (e.g., crane runways, bridge details under traffic), S275JR is suitable, but the design must follow specific fatigue detail categories and rules (e.g., EN 1993-1-9). Critical fatigue details often require careful fabrication and weld profiling to minimize stress concentrations.
Thickness Limitations for Properties: Designers must always use the mechanical properties (especially yield strength) corresponding to the actual thickness of the part, not the nominal grade strength of 275 MPa.
Not for Quenched and Tempered Parts: S275JR is supplied in the as-rolled state. It is not intended to be subsequently heat-treated (quenched and tempered) to achieve higher strength, as its chemistry is not optimized for that process.