F Numbers
quick lookup of filler metal groupings for welding procedure and performance qualification from master classification assignment data source developed, verified and maintained by Mike Bernasek.  F-number and A-Number assignments are based on the following standards: 

ASME Section IX
Table QW-432 and QW-442
AWS B2.1
Table B1 and B2

AWS A5.1
through A5.36

ISO 15614-1 Table 10 and 11

Quick Lookup Abbreviated Search Title ( Legend ):
F# ( F-Number )
A# ( A-Number )
Spec ( AWS A or ASME SFA Specification number)
Classification ( AWS Filler Metal Classification )
UNS ( Unified Numbering System )
Respective registered trademark owners:
The American Society of Mechanical Engineers
AWS® The American Welding Society
ISO® International Organization for Standardization
WeldOffice® Asmeix Corporation d.b.a. C-spec