What code is referenced regarding the qualification of welders?

The qualification of welders is primarily referenced in ASME Section IX. This code outlines the requirements for the qualification of welding and brazing procedures and the performance qualifications of welders and welding operators. It provides structured guidelines to ensure that welders possess the necessary skills and knowledge to produce welds that meet specific quality standards, which is crucial in industries where safety and integrity are paramount, such as pipeline welding.

ASME Section IX specifies tests that must be undertaken to demonstrate a welder's proficiency, ensuring they can perform to the required standards needed for different welding processes and materials. This makes it a vital resource for organizations needing to certify their welders reliably.

While the other options may involve different aspects of materials and welding processes, they do not focus specifically on welder qualifications the same way ASME Section IX does. API 650, for example, is centered on welded tanks for oil storage, and API 1106 addresses the installation of pipelines and related fittings, while ANSI Z49.1 provides general safety practices in welding but does not specifically cover welder qualification.