The purpose of the PQR (Procedure Qualification Record) is:

The Procedure Qualification Record (PQR) plays a crucial role in the welding industry as it documents the actual welding parameters and variables used during the production of a test coupon. This record includes information such as the type of filler material, welding process, joint design, base materials, and other essential parameters that influence the weld's mechanical properties and quality.

The PQR serves as a comprehensive reference point that establishes whether a welding procedure can produce a weld that meets specified performance requirements. By detailing the welding data and variables, the PQR validates the effectiveness of the welding procedure under the conditions it was executed. This charter is essential for ensuring compliance with industry standards and specifications, allowing for the reproducibility of quality welds.

While the other choices relate to areas of welding and inspection, they do not accurately encapsulate the primary function of the PQR. For instance, establishing welder qualifications is typically covered under a Welder Qualification Record (WQR), while quality control measures and material specifications have broader applications and are not solely defined by the PQR. Thus, option B stands out as it directly aligns with the core purpose of the PQR in welding processes.