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Acceptance limits for incompletely fused arc welded joints


Frequently Asked Questions

Acceptance limits for incomplete fusion imperfections in arc welded joints in steel, nickel, titanium and their alloys (excluding beam welding) are specified in BS EN ISO 5817:2007 (note that acceptance limits for other imperfections are specified too).

Acceptance limits are classified in three different quality levels designated by the letters B, C and D. Level B corresponds to the highest quality requirement, C is intermediate and D is moderate. For each type of imperfection the standard presents sketches and dimensions of the imperfection and the corresponding quality level.

The table below shows a summary of the codes and standards defining acceptance limits for different materials and applications.

Steel, Ni, Ti and their alloys BS EN ISO 5817:2007 Welding – Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) – Quality levels for imperfections.
Aluminium BS EN 10042:2005 Welding – Arc-welded joints in aluminium and its alloys - Quality levels for imperfections.
Pressure vessels PD5500:2012 Specification for unfired fusion welded pressure vessels.
Storage tanks BS EN 14015:2004 Specification for the design and manufacture of site built, vertical, cylindrical, flat-bottomed, above ground, welded, steel tanks for the storage of liquids at ambient temperature and above.
Pipework BS2633:1987 Specification for Class I arc welding of ferritic steel pipework for carrying fluids
Line pipe API 1104:2005  Welding of Pipelines and Related Facilities.

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