En Iso 13920-bf High Quality Today

Example: A 2,500 mm long beam should not bow more than 3 mm over its entire length. For parts where centering is important (e.g., a boss on a plate).

Introduction In the world of metal fabrication and welding, precision is not an option—it is a requirement. However, achieving perfect theoretical dimensions in welded structures is virtually impossible due to thermal distortion, shrinkage, and material inconsistencies. This is where EN ISO 13920-BF comes into play. en iso 13920-bf

Note: For small parts, the tolerance is looser because relative distortion is higher. This is critical for base plates and mounting surfaces. Example: A 2,500 mm long beam should not

(full title: Welding — General tolerances for welded constructions — Linear and angular dimensions — Shape and position ) is the European adoption of the international ISO standard. It serves as a universal reference for permissible deviations in welded assemblies. This is critical for base plates and mounting surfaces

| Toleranced Feature | Inspection Tool | Acceptance Criteria | | :--- | :--- | :--- | | Linear length | Steel tape measure (calibrated) | Measure at room temperature (20°C) | | Flatness | Straight edge + feeler gauge | Feeler must not pass under straight edge | | Flatness (large parts) | Laser tracker or theodolite | Record maximum height difference | | Angular distortion | Bevel protractor or digital angle finder | Check after all welding and cooling | | Symmetry | CMM (Coordinate Measuring Machine) or chalk line | Measure from datum edges |

The standard allows measurement uncertainty. If your caliper has an error of ±0.5 mm and the tolerance is ±2 mm, you are fine. But if the tolerance is ±1 mm, you need a more precise instrument. When to Choose a Different Class Instead of "BF" While Class B is versatile, it is not always the right choice.