For automatic submerged arc welding (SAW), when is a PQR required?

In automatic submerged arc welding (SAW), a Procedure Qualification Record (PQR) is required under specific changes in welding conditions, primarily when the changes could significantly impact the weld quality and mechanical properties.

The requirement for a PQR centers around ensuring the welding process is capable of producing sound welds under the proposed welding parameters. A change in the welding speed or a change in filler material can significantly alter factors like the heat input and cooling rates, which are crucial for achieving desired mechanical properties in the weld. Therefore, a PQR would typically be required for these changes to verify that new parameters still produce acceptable welds.

However, a change in the electrode angle, while it might affect the weld characteristics, does not inherently require a new PQR unless it leads to substantial changes in the heat input or weld bead profile that could compromise the integrity of the weld. In cases where changes could lead to marginal variations in the weld pool or bead shape but maintain similar heat input conditions, a PQR may not be deemed necessary.

In summary, since a change in welding speed and filler material directly influences the welding parameters that are essential for maintaining the quality and integrity of the weld, a PQR would thus be required for those adjustments, distinguishing them from lesser