What are the standard specifications for dimensional tolerances on S275JR steel angles?

The dimensional tolerances for hot-rolled steel angles, including those made of S275JR, are governed not by the material standard (EN 10025-2) but by the dedicated product standard EN 10056-1:2017 - "Specification for hot rolled structural steel equal and unequal leg angles - Part 1: Tolerances on shape and dimensions". This standard defines the permissible deviations from nominal dimensions for commercial quality (Class A) and higher quality (Class B) angles. Key tolerances include: Leg Length (h, b): For common sizes, tolerances are typically ±2 mm or ±3 mm depending on the length and class. Leg Thickness (t): Tolerance is usually specified as ±0.5 mm to ±1.5 mm, depending on nominal thickness. Straightness: Defined as the deviation from a straight edge over a specified length (e.g., 0.15% of the length, but not less than 3mm for Class A). Squareness of Legs: The deviation from a 90° angle between the legs. Mass (Weight) Tolerance: The actual mass per meter can vary from the theoretical mass, typically within ±3.5% to ±5% for standard lengths. These tolerances are essential for fabricators. They account for the inherent variability of the hot-rolling process and ensure that components will fit together during assembly (e.g., bolted connections). For most structural work, Class A tolerances are sufficient. For applications requiring higher precision in fit-up, such as some welded frameworks, the tighter Class B tolerances can be specified. The mill test certificate does not usually list individual dimensional checks but confirms the product was manufactured to the relevant tolerance class of EN 10056-1.