Therefore, for a material to be assigned a P number, it MUST have been tested in accordance with the appropriate ASME/ASTM/UNS standard.
Unassigned materials can, with the following provisos (as set out in section QW-424 of ASME IX), be used to carry out ASME type work:
QW-424 Base metals used for Procedure Qualification
QW-424.1 Base metals are assigned P or S Numbers in QW/QB-422; metals which do not appear in QW/QB-422 are considered to be unassigned metals except as otherwise defined in QW-420.1 for base metals having the same UNS numbers. Unassigned metals shall be identified in the WPS (Welding Procedure Specification) and the PQR (Procedure Qualification Record) by specification, type and grade, or by chemical analysis and mechanical properties etc.
Base Metal(s) for Procedure Qualification Coupon: Any unassigned metal to any other unassigned metal.
Base Metals qualified: The first unassigned metal to the second unassigned metal.
Materials to European standards (e.g. DIN or EN) cannot be assigned P-Numbers unless they have been tested in accordance with the appropriate American codes.
European Standard material could be used to do ASME procedure qualifications provided that it was identified in the WPS and the PQR by specification, type and grade, or by chemical analysis and mechanical properties.
In order to be absolutely certain of the position regarding materials that can be used, you can contact ASME at:
American Society of Mechanical Engineers
Two Park Avenue
New York
NY 10016-5990
e-mail - CustomerCare@asme.org