En Iso — 13920-bf New!

Note: If the drawing explicitly writes "BF", you must clarify with the client. However, standard-compliant codes are: .

However, the combination does not strictly exist in the standard's classification list (which lists AC, AD, BC, and BD). en iso 13920-bf

| Tolerance Class | Typical Application | Cost Impact | | :--- | :--- | :--- | | | Precision machinery, jigs, fixtures | High (requires post-weld machining) | | B (Medium) | General mechanical structures, frames, supports | Optimal (achievable with standard welding) | | C (Coarse) | Heavy construction, shipbuilding, basic frames | Low (minimal inspection) | | D/E (Very coarse) | Simple structural steel, agricultural equipment | Very low | Note: If the drawing explicitly writes "BF", you

Class B does not account for accumulated shrinkage. If you weld a 10-meter truss, expect 5–10 mm of overall shrinkage. The tolerance of ±8 mm may still be violated if you do not pre-set angles or use back-step welding techniques. | Tolerance Class | Typical Application | Cost